chai.js

(function(f){if(typeof exports==="object"&&typeof module!=="undefined"){module.exports=f()}else if(typeof define==="function"&&define.amd){define([],f)}else{var g;if(typeof window!=="undefined"){g=window}else if(typeof global!=="undefined"){g=global}else if(typeof self!=="undefined"){g=self}else{g=this}g.chai = f()}})(function(){var define,module,exports;return (function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(require,module,exports){
module.exports = require('./lib/chai');

},{"./lib/chai":2}],2:[function(require,module,exports){
/*!
 * chai
 * Copyright(c) 2011-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

var used = []
  , exports = module.exports = {};

/*!
 * Chai version
 */

exports.version = '3.5.0';

/*!
 * Assertion Error
 */

exports.AssertionError = require('assertion-error');

/*!
 * Utils for plugins (not exported)
 */

var util = require('./chai/utils');

/**
 * # .use(function)
 *
 * Provides a way to extend the internals of Chai
 *
 * @param {Function}
 * @returns {this} for chaining
 * @api public
 */

exports.use = function (fn) {
  if (!~used.indexOf(fn)) {
    fn(this, util);
    used.push(fn);
  }

  return this;
};

/*!
 * Utility Functions
 */

exports.util = util;

/*!
 * Configuration
 */

var config = require('./chai/config');
exports.config = config;

/*!
 * Primary `Assertion` prototype
 */

var assertion = require('./chai/assertion');
exports.use(assertion);

/*!
 * Core Assertions
 */

var core = require('./chai/core/assertions');
exports.use(core);

/*!
 * Expect interface
 */

var expect = require('./chai/interface/expect');
exports.use(expect);

/*!
 * Should interface
 */

var should = require('./chai/interface/should');
exports.use(should);

/*!
 * Assert interface
 */

var assert = require('./chai/interface/assert');
exports.use(assert);

},{"./chai/assertion":3,"./chai/config":4,"./chai/core/assertions":5,"./chai/interface/assert":6,"./chai/interface/expect":7,"./chai/interface/should":8,"./chai/utils":22,"assertion-error":30}],3:[function(require,module,exports){
/*!
 * chai
 * http://chaijs.com
 * Copyright(c) 2011-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

var config = require('./config');

module.exports = function (_chai, util) {
  /*!
   * Module dependencies.
   */

  var AssertionError = _chai.AssertionError
    , flag = util.flag;

  /*!
   * Module export.
   */

  _chai.Assertion = Assertion;

  /*!
   * Assertion Constructor
   *
   * Creates object for chaining.
   *
   * @api private
   */

  function Assertion (obj, msg, stack) {
    flag(this, 'ssfi', stack || arguments.callee);
    flag(this, 'object', obj);
    flag(this, 'message', msg);
  }

  Object.defineProperty(Assertion, 'includeStack', {
    get: function() {
      console.warn('Assertion.includeStack is deprecated, use chai.config.includeStack instead.');
      return config.includeStack;
    },
    set: function(value) {
      console.warn('Assertion.includeStack is deprecated, use chai.config.includeStack instead.');
      config.includeStack = value;
    }
  });

  Object.defineProperty(Assertion, 'showDiff', {
    get: function() {
      console.warn('Assertion.showDiff is deprecated, use chai.config.showDiff instead.');
      return config.showDiff;
    },
    set: function(value) {
      console.warn('Assertion.showDiff is deprecated, use chai.config.showDiff instead.');
      config.showDiff = value;
    }
  });

  Assertion.addProperty = function (name, fn) {
    util.addProperty(this.prototype, name, fn);
  };

  Assertion.addMethod = function (name, fn) {
    util.addMethod(this.prototype, name, fn);
  };

  Assertion.addChainableMethod = function (name, fn, chainingBehavior) {
    util.addChainableMethod(this.prototype, name, fn, chainingBehavior);
  };

  Assertion.overwriteProperty = function (name, fn) {
    util.overwriteProperty(this.prototype, name, fn);
  };

  Assertion.overwriteMethod = function (name, fn) {
    util.overwriteMethod(this.prototype, name, fn);
  };

  Assertion.overwriteChainableMethod = function (name, fn, chainingBehavior) {
    util.overwriteChainableMethod(this.prototype, name, fn, chainingBehavior);
  };

  /**
   * ### .assert(expression, message, negateMessage, expected, actual, showDiff)
   *
   * Executes an expression and check expectations. Throws AssertionError for reporting if test doesn't pass.
   *
   * @name assert
   * @param {Philosophical} expression to be tested
   * @param {String|Function} message or function that returns message to display if expression fails
   * @param {String|Function} negatedMessage or function that returns negatedMessage to display if negated expression fails
   * @param {Mixed} expected value (remember to check for negation)
   * @param {Mixed} actual (optional) will default to `this.obj`
   * @param {Boolean} showDiff (optional) when set to `true`, assert will display a diff in addition to the message if expression fails
   * @api private
   */

  Assertion.prototype.assert = function (expr, msg, negateMsg, expected, _actual, showDiff) {
    var ok = util.test(this, arguments);
    if (true !== showDiff) showDiff = false;
    if (true !== config.showDiff) showDiff = false;

    if (!ok) {
      var msg = util.getMessage(this, arguments)
        , actual = util.getActual(this, arguments);
      throw new AssertionError(msg, {
          actual: actual
        , expected: expected
        , showDiff: showDiff
      }, (config.includeStack) ? this.assert : flag(this, 'ssfi'));
    }
  };

  /*!
   * ### ._obj
   *
   * Quick reference to stored `actual` value for plugin developers.
   *
   * @api private
   */

  Object.defineProperty(Assertion.prototype, '_obj',
    { get: function () {
        return flag(this, 'object');
      }
    , set: function (val) {
        flag(this, 'object', val);
      }
  });
};

},{"./config":4}],4:[function(require,module,exports){
module.exports = {

  /**
   * ### config.includeStack
   *
   * User configurable property, influences whether stack trace
   * is included in Assertion error message. Default of false
   * suppresses stack trace in the error message.
   *
   *     chai.config.includeStack = true;  // enable stack on error
   *
   * @param {Boolean}
   * @api public
   */

   includeStack: false,

  /**
   * ### config.showDiff
   *
   * User configurable property, influences whether or not
   * the `showDiff` flag should be included in the thrown
   * AssertionErrors. `false` will always be `false`; `true`
   * will be true when the assertion has requested a diff
   * be shown.
   *
   * @param {Boolean}
   * @api public
   */

  showDiff: true,

  /**
   * ### config.truncateThreshold
   *
   * User configurable property, sets length threshold for actual and
   * expected values in assertion errors. If this threshold is exceeded, for
   * example for large data structures, the value is replaced with something
   * like `[ Array(3) ]` or `{ Object (prop1, prop2) }`.
   *
   * Set it to zero if you want to disable truncating altogether.
   *
   * This is especially userful when doing assertions on arrays: having this
   * set to a reasonable large value makes the failure messages readily
   * inspectable.
   *
   *     chai.config.truncateThreshold = 0;  // disable truncating
   *
   * @param {Number}
   * @api public
   */

  truncateThreshold: 40

};

},{}],5:[function(require,module,exports){
/*!
 * chai
 * http://chaijs.com
 * Copyright(c) 2011-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

module.exports = function (chai, _) {
  var Assertion = chai.Assertion
    , toString = Object.prototype.toString
    , flag = _.flag;

  /**
   * ### Language Chains
   *
   * The following are provided as chainable getters to
   * improve the readability of your assertions. They
   * do not provide testing capabilities unless they
   * have been overwritten by a plugin.
   *
   * **Chains**
   *
   * - to
   * - be
   * - been
   * - is
   * - that
   * - which
   * - and
   * - has
   * - have
   * - with
   * - at
   * - of
   * - same
   *
   * @name language chains
   * @namespace BDD
   * @api public
   */

  [ 'to', 'be', 'been'
  , 'is', 'and', 'has', 'have'
  , 'with', 'that', 'which', 'at'
  , 'of', 'same' ].forEach(function (chain) {
    Assertion.addProperty(chain, function () {
      return this;
    });
  });

  /**
   * ### .not
   *
   * Negates any of assertions following in the chain.
   *
   *     expect(foo).to.not.equal('bar');
   *     expect(goodFn).to.not.throw(Error);
   *     expect({ foo: 'baz' }).to.have.property('foo')
   *       .and.not.equal('bar');
   *
   * @name not
   * @namespace BDD
   * @api public
   */

  Assertion.addProperty('not', function () {
    flag(this, 'negate', true);
  });

  /**
   * ### .deep
   *
   * Sets the `deep` flag, later used by the `equal` and
   * `property` assertions.
   *
   *     expect(foo).to.deep.equal({ bar: 'baz' });
   *     expect({ foo: { bar: { baz: 'quux' } } })
   *       .to.have.deep.property('foo.bar.baz', 'quux');
   *
   * `.deep.property` special characters can be escaped
   * by adding two slashes before the `.` or `[]`.
   *
   *     var deepCss = { '.link': { '[target]': 42 }};
   *     expect(deepCss).to.have.deep.property('\\.link.\\[target\\]', 42);
   *
   * @name deep
   * @namespace BDD
   * @api public
   */

  Assertion.addProperty('deep', function () {
    flag(this, 'deep', true);
  });

  /**
   * ### .any
   *
   * Sets the `any` flag, (opposite of the `all` flag)
   * later used in the `keys` assertion.
   *
   *     expect(foo).to.have.any.keys('bar', 'baz');
   *
   * @name any
   * @namespace BDD
   * @api public
   */

  Assertion.addProperty('any', function () {
    flag(this, 'any', true);
    flag(this, 'all', false)
  });


  /**
   * ### .all
   *
   * Sets the `all` flag (opposite of the `any` flag)
   * later used by the `keys` assertion.
   *
   *     expect(foo).to.have.all.keys('bar', 'baz');
   *
   * @name all
   * @namespace BDD
   * @api public
   */

  Assertion.addProperty('all', function () {
    flag(this, 'all', true);
    flag(this, 'any', false);
  });

  /**
   * ### .a(type)
   *
   * The `a` and `an` assertions are aliases that can be
   * used either as language chains or to assert a value's
   * type.
   *
   *     // typeof
   *     expect('test').to.be.a('string');
   *     expect({ foo: 'bar' }).to.be.an('object');
   *     expect(null).to.be.a('null');
   *     expect(undefined).to.be.an('undefined');
   *     expect(new Error).to.be.an('error');
   *     expect(new Promise).to.be.a('promise');
   *     expect(new Float32Array()).to.be.a('float32array');
   *     expect(Symbol()).to.be.a('symbol');
   *
   *     // es6 overrides
   *     expect({[Symbol.toStringTag]:()=>'foo'}).to.be.a('foo');
   *
   *     // language chain
   *     expect(foo).to.be.an.instanceof(Foo);
   *
   * @name a
   * @alias an
   * @param {String} type
   * @param {String} message _optional_
   * @namespace BDD
   * @api public
   */

  function an (type, msg) {
    if (msg) flag(this, 'message', msg);
    type = type.toLowerCase();
    var obj = flag(this, 'object')
      , article = ~[ 'a', 'e', 'i', 'o', 'u' ].indexOf(type.charAt(0)) ? 'an ' : 'a ';

    this.assert(
        type === _.type(obj)
      , 'expected #{this} to be ' + article + type
      , 'expected #{this} not to be ' + article + type
    );
  }

  Assertion.addChainableMethod('an', an);
  Assertion.addChainableMethod('a', an);

  /**
   * ### .include(value)
   *
   * The `include` and `contain` assertions can be used as either property
   * based language chains or as methods to assert the inclusion of an object
   * in an array or a substring in a string. When used as language chains,
   * they toggle the `contains` flag for the `keys` assertion.
   *
   *     expect([1,2,3]).to.include(2);
   *     expect('foobar').to.contain('foo');
   *     expect({ foo: 'bar', hello: 'universe' }).to.include.keys('foo');
   *
   * @name include
   * @alias contain
   * @alias includes
   * @alias contains
   * @param {Object|String|Number} obj
   * @param {String} message _optional_
   * @namespace BDD
   * @api public
   */

  function includeChainingBehavior () {
    flag(this, 'contains', true);
  }

  function include (val, msg) {
    _.expectTypes(this, ['array', 'object', 'string']);

    if (msg) flag(this, 'message', msg);
    var obj = flag(this, 'object');
    var expected = false;

    if (_.type(obj) === 'array' && _.type(val) === 'object') {
      for (var i in obj) {
        if (_.eql(obj[i], val)) {
          expected = true;
          break;
        }
      }
    } else if (_.type(val) === 'object') {
      if (!flag(this, 'negate')) {
        for (var k in val) new Assertion(obj).property(k, val[k]);
        return;
      }
      var subset = {};
      for (var k in val) subset[k] = obj[k];
      expected = _.eql(subset, val);
    } else {
      expected = (obj != undefined) && ~obj.indexOf(val);
    }
    this.assert(
        expected
      , 'expected #{this} to include ' + _.inspect(val)
      , 'expected #{this} to not include ' + _.inspect(val));
  }

  Assertion.addChainableMethod('include', include, includeChainingBehavior);
  Assertion.addChainableMethod('contain', include, includeChainingBehavior);
  Assertion.addChainableMethod('contains', include, includeChainingBehavior);
  Assertion.addChainableMethod('includes', include, includeChainingBehavior);

  /**
   * ### .ok
   *
   * Asserts that the target is truthy.
   *
   *     expect('everything').to.be.ok;
   *     expect(1).to.be.ok;
   *     expect(false).to.not.be.ok;
   *     expect(undefined).to.not.be.ok;
   *     expect(null).to.not.be.ok;
   *
   * @name ok
   * @namespace BDD
   * @api public
   */

  Assertion.addProperty('ok', function () {
    this.assert(
        flag(this, 'object')
      , 'expected #{this} to be truthy'
      , 'expected #{this} to be falsy');
  });

  /**
   * ### .true
   *
   * Asserts that the target is `true`.
   *
   *     expect(true).to.be.true;
   *     expect(1).to.not.be.true;
   *
   * @name true
   * @namespace BDD
   * @api public
   */

  Assertion.addProperty('true', function () {
    this.assert(
        true === flag(this, 'object')
      , 'expected #{this} to be true'
      , 'expected #{this} to be false'
      , this.negate ? false : true
    );
  });

  /**
   * ### .false
   *
   * Asserts that the target is `false`.
   *
   *     expect(false).to.be.false;
   *     expect(0).to.not.be.false;
   *
   * @name false
   * @namespace BDD
   * @api public
   */

  Assertion.addProperty('false', function () {
    this.assert(
        false === flag(this, 'object')
      , 'expected #{this} to be false'
      , 'expected #{this} to be true'
      , this.negate ? true : false
    );
  });

  /**
   * ### .null
   *
   * Asserts that the target is `null`.
   *
   *     expect(null).to.be.null;
   *     expect(undefined).to.not.be.null;
   *
   * @name null
   * @namespace BDD
   * @api public
   */

  Assertion.addProperty('null', function () {
    this.assert(
        null === flag(this, 'object')
      , 'expected #{this} to be null'
      , 'expected #{this} not to be null'
    );
  });

  /**
   * ### .undefined
   *
   * Asserts that the target is `undefined`.
   *
   *     expect(undefined).to.be.undefined;
   *     expect(null).to.not.be.undefined;
   *
   * @name undefined
   * @namespace BDD
   * @api public
   */

  Assertion.addProperty('undefined', function () {
    this.assert(
        undefined === flag(this, 'object')
      , 'expected #{this} to be undefined'
      , 'expected #{this} not to be undefined'
    );
  });

  /**
   * ### .NaN
   * Asserts that the target is `NaN`.
   *
   *     expect('foo').to.be.NaN;
   *     expect(4).not.to.be.NaN;
   *
   * @name NaN
   * @namespace BDD
   * @api public
   */

  Assertion.addProperty('NaN', function () {
    this.assert(
        isNaN(flag(this, 'object'))
        , 'expected #{this} to be NaN'
        , 'expected #{this} not to be NaN'
    );
  });

  /**
   * ### .exist
   *
   * Asserts that the target is neither `null` nor `undefined`.
   *
   *     var foo = 'hi'
   *       , bar = null
   *       , baz;
   *
   *     expect(foo).to.exist;
   *     expect(bar).to.not.exist;
   *     expect(baz).to.not.exist;
   *
   * @name exist
   * @namespace BDD
   * @api public
   */

  Assertion.addProperty('exist', function () {
    this.assert(
        null != flag(this, 'object')
      , 'expected #{this} to exist'
      , 'expected #{this} to not exist'
    );
  });


  /**
   * ### .empty
   *
   * Asserts that the target's length is `0`. For arrays and strings, it checks
   * the `length` property. For objects, it gets the count of
   * enumerable keys.
   *
   *     expect([]).to.be.empty;
   *     expect('').to.be.empty;
   *     expect({}).to.be.empty;
   *
   * @name empty
   * @namespace BDD
   * @api public
   */

  Assertion.addProperty('empty', function () {
    var obj = flag(this, 'object')
      , expected = obj;

    if (Array.isArray(obj) || 'string' === typeof object) {
      expected = obj.length;
    } else if (typeof obj === 'object') {
      expected = Object.keys(obj).length;
    }

    this.assert(
        !expected
      , 'expected #{this} to be empty'
      , 'expected #{this} not to be empty'
    );
  });

  /**
   * ### .arguments
   *
   * Asserts that the target is an arguments object.
   *
   *     function test () {
   *       expect(arguments).to.be.arguments;
   *     }
   *
   * @name arguments
   * @alias Arguments
   * @namespace BDD
   * @api public
   */

  function checkArguments () {
    var obj = flag(this, 'object')
      , type = Object.prototype.toString.call(obj);
    this.assert(
        '[object Arguments]' === type
      , 'expected #{this} to be arguments but got ' + type
      , 'expected #{this} to not be arguments'
    );
  }

  Assertion.addProperty('arguments', checkArguments);
  Assertion.addProperty('Arguments', checkArguments);

  /**
   * ### .equal(value)
   *
   * Asserts that the target is strictly equal (`===`) to `value`.
   * Alternately, if the `deep` flag is set, asserts that
   * the target is deeply equal to `value`.
   *
   *     expect('hello').to.equal('hello');
   *     expect(42).to.equal(42);
   *     expect(1).to.not.equal(true);
   *     expect({ foo: 'bar' }).to.not.equal({ foo: 'bar' });
   *     expect({ foo: 'bar' }).to.deep.equal({ foo: 'bar' });
   *
   * @name equal
   * @alias equals
   * @alias eq
   * @alias deep.equal
   * @param {Mixed} value
   * @param {String} message _optional_
   * @namespace BDD
   * @api public
   */

  function assertEqual (val, msg) {
    if (msg) flag(this, 'message', msg);
    var obj = flag(this, 'object');
    if (flag(this, 'deep')) {
      return this.eql(val);
    } else {
      this.assert(
          val === obj
        , 'expected #{this} to equal #{exp}'
        , 'expected #{this} to not equal #{exp}'
        , val
        , this._obj
        , true
      );
    }
  }

  Assertion.addMethod('equal', assertEqual);
  Assertion.addMethod('equals', assertEqual);
  Assertion.addMethod('eq', assertEqual);

  /**
   * ### .eql(value)
   *
   * Asserts that the target is deeply equal to `value`.
   *
   *     expect({ foo: 'bar' }).to.eql({ foo: 'bar' });
   *     expect([ 1, 2, 3 ]).to.eql([ 1, 2, 3 ]);
   *
   * @name eql
   * @alias eqls
   * @param {Mixed} value
   * @param {String} message _optional_
   * @namespace BDD
   * @api public
   */

  function assertEql(obj, msg) {
    if (msg) flag(this, 'message', msg);
    this.assert(
        _.eql(obj, flag(this, 'object'))
      , 'expected #{this} to deeply equal #{exp}'
      , 'expected #{this} to not deeply equal #{exp}'
      , obj
      , this._obj
      , true
    );
  }

  Assertion.addMethod('eql', assertEql);
  Assertion.addMethod('eqls', assertEql);

  /**
   * ### .above(value)
   *
   * Asserts that the target is greater than `value`.
   *
   *     expect(10).to.be.above(5);
   *
   * Can also be used in conjunction with `length` to
   * assert a minimum length. The benefit being a
   * more informative error message than if the length
   * was supplied directly.
   *
   *     expect('foo').to.have.length.above(2);
   *     expect([ 1, 2, 3 ]).to.have.length.above(2);
   *
   * @name above
   * @alias gt
   * @alias greaterThan
   * @param {Number} value
   * @param {String} message _optional_
   * @namespace BDD
   * @api public
   */

  function assertAbove (n, msg) {
    if (msg) flag(this, 'message', msg);
    var obj = flag(this, 'object');
    if (flag(this, 'doLength')) {
      new Assertion(obj, msg).to.have.property('length');
      var len = obj.length;
      this.assert(
          len > n
        , 'expected #{this} to have a length above #{exp} but got #{act}'
        , 'expected #{this} to not have a length above #{exp}'
        , n
        , len
      );
    } else {
      this.assert(
          obj > n
        , 'expected #{this} to be above ' + n
        , 'expected #{this} to be at most ' + n
      );
    }
  }

  Assertion.addMethod('above', assertAbove);
  Assertion.addMethod('gt', assertAbove);
  Assertion.addMethod('greaterThan', assertAbove);

  /**
   * ### .least(value)
   *
   * Asserts that the target is greater than or equal to `value`.
   *
   *     expect(10).to.be.at.least(10);
   *
   * Can also be used in conjunction with `length` to
   * assert a minimum length. The benefit being a
   * more informative error message than if the length
   * was supplied directly.
   *
   *     expect('foo').to.have.length.of.at.least(2);
   *     expect([ 1, 2, 3 ]).to.have.length.of.at.least(3);
   *
   * @name least
   * @alias gte
   * @param {Number} value
   * @param {String} message _optional_
   * @namespace BDD
   * @api public
   */

  function assertLeast (n, msg) {
    if (msg) flag(this, 'message', msg);
    var obj = flag(this, 'object');
    if (flag(this, 'doLength')) {
      new Assertion(obj, msg).to.have.property('length');
      var len = obj.length;
      this.assert(
          len >= n
        , 'expected #{this} to have a length at least #{exp} but got #{act}'
        , 'expected #{this} to have a length below #{exp}'
        , n
        , len
      );
    } else {
      this.assert(
          obj >= n
        , 'expected #{this} to be at least ' + n
        , 'expected #{this} to be below ' + n
      );
    }
  }

  Assertion.addMethod('least', assertLeast);
  Assertion.addMethod('gte', assertLeast);

  /**
   * ### .below(value)
   *
   * Asserts that the target is less than `value`.
   *
   *     expect(5).to.be.below(10);
   *
   * Can also be used in conjunction with `length` to
   * assert a maximum length. The benefit being a
   * more informative error message than if the length
   * was supplied directly.
   *
   *     expect('foo').to.have.length.below(4);
   *     expect([ 1, 2, 3 ]).to.have.length.below(4);
   *
   * @name below
   * @alias lt
   * @alias lessThan
   * @param {Number} value
   * @param {String} message _optional_
   * @namespace BDD
   * @api public
   */

  function assertBelow (n, msg) {
    if (msg) flag(this, 'message', msg);
    var obj = flag(this, 'object');
    if (flag(this, 'doLength')) {
      new Assertion(obj, msg).to.have.property('length');
      var len = obj.length;
      this.assert(
          len < n
        , 'expected #{this} to have a length below #{exp} but got #{act}'
        , 'expected #{this} to not have a length below #{exp}'
        , n
        , len
      );
    } else {
      this.assert(
          obj < n
        , 'expected #{this} to be below ' + n
        , 'expected #{this} to be at least ' + n
      );
    }
  }

  Assertion.addMethod('below', assertBelow);
  Assertion.addMethod('lt', assertBelow);
  Assertion.addMethod('lessThan', assertBelow);

  /**
   * ### .most(value)
   *
   * Asserts that the target is less than or equal to `value`.
   *
   *     expect(5).to.be.at.most(5);
   *
   * Can also be used in conjunction with `length` to
   * assert a maximum length. The benefit being a
   * more informative error message than if the length
   * was supplied directly.
   *
   *     expect('foo').to.have.length.of.at.most(4);
   *     expect([ 1, 2, 3 ]).to.have.length.of.at.most(3);
   *
   * @name most
   * @alias lte
   * @param {Number} value
   * @param {String} message _optional_
   * @namespace BDD
   * @api public
   */

  function assertMost (n, msg) {
    if (msg) flag(this, 'message', msg);
    var obj = flag(this, 'object');
    if (flag(this, 'doLength')) {
      new Assertion(obj, msg).to.have.property('length');
      var len = obj.length;
      this.assert(
          len <= n
        , 'expected #{this} to have a length at most #{exp} but got #{act}'
        , 'expected #{this} to have a length above #{exp}'
        , n
        , len
      );
    } else {
      this.assert(
          obj <= n
        , 'expected #{this} to be at most ' + n
        , 'expected #{this} to be above ' + n
      );
    }
  }

  Assertion.addMethod('most', assertMost);
  Assertion.addMethod('lte', assertMost);

  /**
   * ### .within(start, finish)
   *
   * Asserts that the target is within a range.
   *
   *     expect(7).to.be.within(5,10);
   *
   * Can also be used in conjunction with `length` to
   * assert a length range. The benefit being a
   * more informative error message than if the length
   * was supplied directly.
   *
   *     expect('foo').to.have.length.within(2,4);
   *     expect([ 1, 2, 3 ]).to.have.length.within(2,4);
   *
   * @name within
   * @param {Number} start lowerbound inclusive
   * @param {Number} finish upperbound inclusive
   * @param {String} message _optional_
   * @namespace BDD
   * @api public
   */

  Assertion.addMethod('within', function (start, finish, msg) {
    if (msg) flag(this, 'message', msg);
    var obj = flag(this, 'object')
      , range = start + '..' + finish;
    if (flag(this, 'doLength')) {
      new Assertion(obj, msg).to.have.property('length');
      var len = obj.length;
      this.assert(
          len >= start && len <= finish
        , 'expected #{this} to have a length within ' + range
        , 'expected #{this} to not have a length within ' + range
      );
    } else {
      this.assert(
          obj >= start && obj <= finish
        , 'expected #{this} to be within ' + range
        , 'expected #{this} to not be within ' + range
      );
    }
  });

  /**
   * ### .instanceof(constructor)
   *
   * Asserts that the target is an instance of `constructor`.
   *
   *     var Tea = function (name) { this.name = name; }
   *       , Chai = new Tea('chai');
   *
   *     expect(Chai).to.be.an.instanceof(Tea);
   *     expect([ 1, 2, 3 ]).to.be.instanceof(Array);
   *
   * @name instanceof
   * @param {Constructor} constructor
   * @param {String} message _optional_
   * @alias instanceOf
   * @namespace BDD
   * @api public
   */

  function assertInstanceOf (constructor, msg) {
    if (msg) flag(this, 'message', msg);
    var name = _.getName(constructor);
    this.assert(
        flag(this, 'object') instanceof constructor
      , 'expected #{this} to be an instance of ' + name
      , 'expected #{this} to not be an instance of ' + name
    );
  };

  Assertion.addMethod('instanceof', assertInstanceOf);
  Assertion.addMethod('instanceOf', assertInstanceOf);

  /**
   * ### .property(name, [value])
   *
   * Asserts that the target has a property `name`, optionally asserting that
   * the value of that property is strictly equal to  `value`.
   * If the `deep` flag is set, you can use dot- and bracket-notation for deep
   * references into objects and arrays.
   *
   *     // simple referencing
   *     var obj = { foo: 'bar' };
   *     expect(obj).to.have.property('foo');
   *     expect(obj).to.have.property('foo', 'bar');
   *
   *     // deep referencing
   *     var deepObj = {
   *         green: { tea: 'matcha' }
   *       , teas: [ 'chai', 'matcha', { tea: 'konacha' } ]
   *     };
   *
   *     expect(deepObj).to.have.deep.property('green.tea', 'matcha');
   *     expect(deepObj).to.have.deep.property('teas[1]', 'matcha');
   *     expect(deepObj).to.have.deep.property('teas[2].tea', 'konacha');
   *
   * You can also use an array as the starting point of a `deep.property`
   * assertion, or traverse nested arrays.
   *
   *     var arr = [
   *         [ 'chai', 'matcha', 'konacha' ]
   *       , [ { tea: 'chai' }
   *         , { tea: 'matcha' }
   *         , { tea: 'konacha' } ]
   *     ];
   *
   *     expect(arr).to.have.deep.property('[0][1]', 'matcha');
   *     expect(arr).to.have.deep.property('[1][2].tea', 'konacha');
   *
   * Furthermore, `property` changes the subject of the assertion
   * to be the value of that property from the original object. This
   * permits for further chainable assertions on that property.
   *
   *     expect(obj).to.have.property('foo')
   *       .that.is.a('string');
   *     expect(deepObj).to.have.property('green')
   *       .that.is.an('object')
   *       .that.deep.equals({ tea: 'matcha' });
   *     expect(deepObj).to.have.property('teas')
   *       .that.is.an('array')
   *       .with.deep.property('[2]')
   *         .that.deep.equals({ tea: 'konacha' });
   *
   * Note that dots and bracket in `name` must be backslash-escaped when
   * the `deep` flag is set, while they must NOT be escaped when the `deep`
   * flag is not set.
   *
   *     // simple referencing
   *     var css = { '.link[target]': 42 };
   *     expect(css).to.have.property('.link[target]', 42);
   *
   *     // deep referencing
   *     var deepCss = { '.link': { '[target]': 42 }};
   *     expect(deepCss).to.have.deep.property('\\.link.\\[target\\]', 42);
   *
   * @name property
   * @alias deep.property
   * @param {String} name
   * @param {Mixed} value (optional)
   * @param {String} message _optional_
   * @returns value of property for chaining
   * @namespace BDD
   * @api public
   */

  Assertion.addMethod('property', function (name, val, msg) {
    if (msg) flag(this, 'message', msg);

    var isDeep = !!flag(this, 'deep')
      , descriptor = isDeep ? 'deep property ' : 'property '
      , negate = flag(this, 'negate')
      , obj = flag(this, 'object')
      , pathInfo = isDeep ? _.getPathInfo(name, obj) : null
      , hasProperty = isDeep
        ? pathInfo.exists
        : _.hasProperty(name, obj)
      , value = isDeep
        ? pathInfo.value
        : obj[name];

    if (negate && arguments.length > 1) {
      if (undefined === value) {
        msg = (msg != null) ? msg + ': ' : '';
        throw new Error(msg + _.inspect(obj) + ' has no ' + descriptor + _.inspect(name));
      }
    } else {
      this.assert(
          hasProperty
        , 'expected #{this} to have a ' + descriptor + _.inspect(name)
        , 'expected #{this} to not have ' + descriptor + _.inspect(name));
    }

    if (arguments.length > 1) {
      this.assert(
          val === value
        , 'expected #{this} to have a ' + descriptor + _.inspect(name) + ' of #{exp}, but got #{act}'
        , 'expected #{this} to not have a ' + descriptor + _.inspect(name) + ' of #{act}'
        , val
        , value
      );
    }

    flag(this, 'object', value);
  });


  /**
   * ### .ownProperty(name)
   *
   * Asserts that the target has an own property `name`.
   *
   *     expect('test').to.have.ownProperty('length');
   *
   * @name ownProperty
   * @alias haveOwnProperty
   * @param {String} name
   * @param {String} message _optional_
   * @namespace BDD
   * @api public
   */

  function assertOwnProperty (name, msg) {
    if (msg) flag(this, 'message', msg);
    var obj = flag(this, 'object');
    this.assert(
        obj.hasOwnProperty(name)
      , 'expected #{this} to have own property ' + _.inspect(name)
      , 'expected #{this} to not have own property ' + _.inspect(name)
    );
  }

  Assertion.addMethod('ownProperty', assertOwnProperty);
  Assertion.addMethod('haveOwnProperty', assertOwnProperty);

  /**
   * ### .ownPropertyDescriptor(name[, descriptor[, message]])
   *
   * Asserts that the target has an own property descriptor `name`, that optionally matches `descriptor`.
   *
   *     expect('test').to.have.ownPropertyDescriptor('length');
   *     expect('test').to.have.ownPropertyDescriptor('length', { enumerable: false, configurable: false, writable: false, value: 4 });
   *     expect('test').not.to.have.ownPropertyDescriptor('length', { enumerable: false, configurable: false, writable: false, value: 3 });
   *     expect('test').ownPropertyDescriptor('length').to.have.property('enumerable', false);
   *     expect('test').ownPropertyDescriptor('length').to.have.keys('value');
   *
   * @name ownPropertyDescriptor
   * @alias haveOwnPropertyDescriptor
   * @param {String} name
   * @param {Object} descriptor _optional_
   * @param {String} message _optional_
   * @namespace BDD
   * @api public
   */

  function assertOwnPropertyDescriptor (name, descriptor, msg) {
    if (typeof descriptor === 'string') {
      msg = descriptor;
      descriptor = null;
    }
    if (msg) flag(this, 'message', msg);
    var obj = flag(this, 'object');
    var actualDescriptor = Object.getOwnPropertyDescriptor(Object(obj), name);
    if (actualDescriptor && descriptor) {
      this.assert(
          _.eql(descriptor, actualDescriptor)
        , 'expected the own property descriptor for ' + _.inspect(name) + ' on #{this} to match ' + _.inspect(descriptor) + ', got ' + _.inspect(actualDescriptor)
        , 'expected the own property descriptor for ' + _.inspect(name) + ' on #{this} to not match ' + _.inspect(descriptor)
        , descriptor
        , actualDescriptor
        , true
      );
    } else {
      this.assert(
          actualDescriptor
        , 'expected #{this} to have an own property descriptor for ' + _.inspect(name)
        , 'expected #{this} to not have an own property descriptor for ' + _.inspect(name)
      );
    }
    flag(this, 'object', actualDescriptor);
  }

  Assertion.addMethod('ownPropertyDescriptor', assertOwnPropertyDescriptor);
  Assertion.addMethod('haveOwnPropertyDescriptor', assertOwnPropertyDescriptor);

  /**
   * ### .length
   *
   * Sets the `doLength` flag later used as a chain precursor to a value
   * comparison for the `length` property.
   *
   *     expect('foo').to.have.length.above(2);
   *     expect([ 1, 2, 3 ]).to.have.length.above(2);
   *     expect('foo').to.have.length.below(4);
   *     expect([ 1, 2, 3 ]).to.have.length.below(4);
   *     expect('foo').to.have.length.within(2,4);
   *     expect([ 1, 2, 3 ]).to.have.length.within(2,4);
   *
   * *Deprecation notice:* Using `length` as an assertion will be deprecated
   * in version 2.4.0 and removed in 3.0.0. Code using the old style of
   * asserting for `length` property value using `length(value)` should be
   * switched to use `lengthOf(value)` instead.
   *
   * @name length
   * @namespace BDD
   * @api public
   */

  /**
   * ### .lengthOf(value[, message])
   *
   * Asserts that the target's `length` property has
   * the expected value.
   *
   *     expect([ 1, 2, 3]).to.have.lengthOf(3);
   *     expect('foobar').to.have.lengthOf(6);
   *
   * @name lengthOf
   * @param {Number} length
   * @param {String} message _optional_
   * @namespace BDD
   * @api public
   */

  function assertLengthChain () {
    flag(this, 'doLength', true);
  }

  function assertLength (n, msg) {
    if (msg) flag(this, 'message', msg);
    var obj = flag(this, 'object');
    new Assertion(obj, msg).to.have.property('length');
    var len = obj.length;

    this.assert(
        len == n
      , 'expected #{this} to have a length of #{exp} but got #{act}'
      , 'expected #{this} to not have a length of #{act}'
      , n
      , len
    );
  }

  Assertion.addChainableMethod('length', assertLength, assertLengthChain);
  Assertion.addMethod('lengthOf', assertLength);

  /**
   * ### .match(regexp)
   *
   * Asserts that the target matches a regular expression.
   *
   *     expect('foobar').to.match(/^foo/);
   *
   * @name match
   * @alias matches
   * @param {RegExp} RegularExpression
   * @param {String} message _optional_
   * @namespace BDD
   * @api public
   */
  function assertMatch(re, msg) {
    if (msg) flag(this, 'message', msg);
    var obj = flag(this, 'object');
    this.assert(
        re.exec(obj)
      , 'expected #{this} to match ' + re
      , 'expected #{this} not to match ' + re
    );
  }

  Assertion.addMethod('match', assertMatch);
  Assertion.addMethod('matches', assertMatch);

  /**
   * ### .string(string)
   *
   * Asserts that the string target contains another string.
   *
   *     expect('foobar').to.have.string('bar');
   *
   * @name string
   * @param {String} string
   * @param {String} message _optional_
   * @namespace BDD
   * @api public
   */

  Assertion.addMethod('string', function (str, msg) {
    if (msg) flag(this, 'message', msg);
    var obj = flag(this, 'object');
    new Assertion(obj, msg).is.a('string');

    this.assert(
        ~obj.indexOf(str)
      , 'expected #{this} to contain ' + _.inspect(str)
      , 'expected #{this} to not contain ' + _.inspect(str)
    );
  });


  /**
   * ### .keys(key1, [key2], [...])
   *
   * Asserts that the target contains any or all of the passed-in keys.
   * Use in combination with `any`, `all`, `contains`, or `have` will affect
   * what will pass.
   *
   * When used in conjunction with `any`, at least one key that is passed
   * in must exist in the target object. This is regardless whether or not
   * the `have` or `contain` qualifiers are used. Note, either `any` or `all`
   * should be used in the assertion. If neither are used, the assertion is
   * defaulted to `all`.
   *
   * When both `all` and `contain` are used, the target object must have at
   * least all of the passed-in keys but may have more keys not listed.
   *
   * When both `all` and `have` are used, the target object must both contain
   * all of the passed-in keys AND the number of keys in the target object must
   * match the number of keys passed in (in other words, a target object must
   * have all and only all of the passed-in keys).
   *
   *     expect({ foo: 1, bar: 2 }).to.have.any.keys('foo', 'baz');
   *     expect({ foo: 1, bar: 2 }).to.have.any.keys('foo');
   *     expect({ foo: 1, bar: 2 }).to.contain.any.keys('bar', 'baz');
   *     expect({ foo: 1, bar: 2 }).to.contain.any.keys(['foo']);
   *     expect({ foo: 1, bar: 2 }).to.contain.any.keys({'foo': 6});
   *     expect({ foo: 1, bar: 2 }).to.have.all.keys(['bar', 'foo']);
   *     expect({ foo: 1, bar: 2 }).to.have.all.keys({'bar': 6, 'foo': 7});
   *     expect({ foo: 1, bar: 2, baz: 3 }).to.contain.all.keys(['bar', 'foo']);
   *     expect({ foo: 1, bar: 2, baz: 3 }).to.contain.all.keys({'bar': 6});
   *
   *
   * @name keys
   * @alias key
   * @param {...String|Array|Object} keys
   * @namespace BDD
   * @api public
   */

  function assertKeys (keys) {
    var obj = flag(this, 'object')
      , str
      , ok = true
      , mixedArgsMsg = 'keys must be given single argument of Array|Object|String, or multiple String arguments';

    switch (_.type(keys)) {
      case "array":
        if (arguments.length > 1) throw (new Error(mixedArgsMsg));
        break;
      case "object":
        if (arguments.length > 1) throw (new Error(mixedArgsMsg));
        keys = Object.keys(keys);
        break;
      default:
        keys = Array.prototype.slice.call(arguments);
    }

    if (!keys.length) throw new Error('keys required');

    var actual = Object.keys(obj)
      , expected = keys
      , len = keys.length
      , any = flag(this, 'any')
      , all = flag(this, 'all');

    if (!any && !all) {
      all = true;
    }

    // Has any
    if (any) {
      var intersection = expected.filter(function(key) {
        return ~actual.indexOf(key);
      });
      ok = intersection.length > 0;
    }

    // Has all
    if (all) {
      ok = keys.every(function(key){
        return ~actual.indexOf(key);
      });
      if (!flag(this, 'negate') && !flag(this, 'contains')) {
        ok = ok && keys.length == actual.length;
      }
    }

    // Key string
    if (len > 1) {
      keys = keys.map(function(key){
        return _.inspect(key);
      });
      var last = keys.pop();
      if (all) {
        str = keys.join(', ') + ', and ' + last;
      }
      if (any) {
        str = keys.join(', ') + ', or ' + last;
      }
    } else {
      str = _.inspect(keys[0]);
    }

    // Form
    str = (len > 1 ? 'keys ' : 'key ') + str;

    // Have / include
    str = (flag(this, 'contains') ? 'contain ' : 'have ') + str;

    // Assertion
    this.assert(
        ok
      , 'expected #{this} to ' + str
      , 'expected #{this} to not ' + str
      , expected.slice(0).sort()
      , actual.sort()
      , true
    );
  }

  Assertion.addMethod('keys', assertKeys);
  Assertion.addMethod('key', assertKeys);

  /**
   * ### .throw(constructor)
   *
   * Asserts that the function target will throw a specific error, or specific type of error
   * (as determined using `instanceof`), optionally with a RegExp or string inclusion test
   * for the error's message.
   *
   *     var err = new ReferenceError('This is a bad function.');
   *     var fn = function () { throw err; }
   *     expect(fn).to.throw(ReferenceError);
   *     expect(fn).to.throw(Error);
   *     expect(fn).to.throw(/bad function/);
   *     expect(fn).to.not.throw('good function');
   *     expect(fn).to.throw(ReferenceError, /bad function/);
   *     expect(fn).to.throw(err);
   *
   * Please note that when a throw expectation is negated, it will check each
   * parameter independently, starting with error constructor type. The appropriate way
   * to check for the existence of a type of error but for a message that does not match
   * is to use `and`.
   *
   *     expect(fn).to.throw(ReferenceError)
   *        .and.not.throw(/good function/);
   *
   * To check a function with arguments you can wrap the call in an anonymous function:
   *
   *     expect(function() { fn('arg1', 2) }).to.throw(ReferenceError);
   *
   * If you need some more complicated check you can chain `throws` with `satisfy`
   *
   *     expect(fn).to.throw().and.to.satisfy((error) => {
   *       return error.code === 404;
   *     });
   *
   * or even more appropriate method which gives better error message in case of fail
   *
   *     expect(fn).to.throw(Error).which.has.property('code', 404);
   *
   *     expect(fn).to.throw(Error).which.has.property('code').that.is.within(399, 500);
   *
   * @name throw
   * @alias throws
   * @alias Throw
   * @param {ErrorConstructor} constructor
   * @param {String|RegExp} expected error message
   * @param {String} message _optional_
   * @see https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Error#Error_types
   * @returns error for chaining (null if no error)
   * @namespace BDD
   * @api public
   */

  function assertThrows (constructor, errMsg, msg) {
    if (msg) flag(this, 'message', msg);
    var obj = flag(this, 'object');
    new Assertion(obj, msg).is.a('function');

    var thrown = false
      , desiredError = null
      , name = null
      , thrownError = null;

    if (arguments.length === 0) {
      errMsg = null;
      constructor = null;
    } else if (constructor && (constructor instanceof RegExp || 'string' === typeof constructor)) {
      errMsg = constructor;
      constructor = null;
    } else if (constructor && constructor instanceof Error) {
      desiredError = constructor;
      constructor = null;
      errMsg = null;
    } else if (typeof constructor === 'function') {
      name = constructor.prototype.name;
      if (!name || (name === 'Error' && constructor !== Error)) {
        name = constructor.name || (new constructor()).name;
      }
    } else {
      constructor = null;
    }

    try {
      obj();
    } catch (err) {
      // first, check desired error
      if (desiredError) {
        this.assert(
            err === desiredError
          , 'expected #{this} to throw #{exp} but #{act} was thrown'
          , 'expected #{this} to not throw #{exp}'
          , (desiredError instanceof Error ? desiredError.toString() : desiredError)
          , (err instanceof Error ? err.toString() : err)
        );

        flag(this, 'object', err);
        return this;
      }

      // next, check constructor
      if (constructor) {
        this.assert(
            err instanceof constructor
          , 'expected #{this} to throw #{exp} but #{act} was thrown'
          , 'expected #{this} to not throw #{exp} but #{act} was thrown'
          , name
          , (err instanceof Error ? err.toString() : err)
        );

        if (!errMsg) {
          flag(this, 'object', err);
          return this;
        }
      }

      // next, check message
      var message = 'error' === _.type(err) && "message" in err
        ? err.message
        : '' + err;

      if ((message != null) && errMsg && errMsg instanceof RegExp) {
        this.assert(
            errMsg.exec(message)
          , 'expected #{this} to throw error matching #{exp} but got #{act}'
          , 'expected #{this} to throw error not matching #{exp}'
          , errMsg
          , message
        );

        flag(this, 'object', err);
        return this;
      } else if ((message != null) && errMsg && 'string' === typeof errMsg) {
        this.assert(
            ~message.indexOf(errMsg)
          , 'expected #{this} to throw error including #{exp} but got #{act}'
          , 'expected #{this} to throw error not including #{act}'
          , errMsg
          , message
        );

        flag(this, 'object', err);
        return this;
      } else {
        thrown = true;
        thrownError = err;
      }
    }

    var actuallyGot = ''
      , expectedThrown = name !== null
        ? name
        : desiredError
          ? '#{exp}' //_.inspect(desiredError)
          : 'an error';

    if (thrown) {
      actuallyGot = ' but #{act} was thrown'
    }

    this.assert(
        thrown === true
      , 'expected #{this} to throw ' + expectedThrown + actuallyGot
      , 'expected #{this} to not throw ' + expectedThrown + actuallyGot
      , (desiredError instanceof Error ? desiredError.toString() : desiredError)
      , (thrownError instanceof Error ? thrownError.toString() : thrownError)
    );

    flag(this, 'object', thrownError);
  };

  Assertion.addMethod('throw', assertThrows);
  Assertion.addMethod('throws', assertThrows);
  Assertion.addMethod('Throw', assertThrows);

  /**
   * ### .respondTo(method)
   *
   * Asserts that the object or class target will respond to a method.
   *
   *     Klass.prototype.bar = function(){};
   *     expect(Klass).to.respondTo('bar');
   *     expect(obj).to.respondTo('bar');
   *
   * To check if a constructor will respond to a static function,
   * set the `itself` flag.
   *
   *     Klass.baz = function(){};
   *     expect(Klass).itself.to.respondTo('baz');
   *
   * @name respondTo
   * @alias respondsTo
   * @param {String} method
   * @param {String} message _optional_
   * @namespace BDD
   * @api public
   */

  function respondTo (method, msg) {
    if (msg) flag(this, 'message', msg);
    var obj = flag(this, 'object')
      , itself = flag(this, 'itself')
      , context = ('function' === _.type(obj) && !itself)
        ? obj.prototype[method]
        : obj[method];

    this.assert(
        'function' === typeof context
      , 'expected #{this} to respond to ' + _.inspect(method)
      , 'expected #{this} to not respond to ' + _.inspect(method)
    );
  }

  Assertion.addMethod('respondTo', respondTo);
  Assertion.addMethod('respondsTo', respondTo);

  /**
   * ### .itself
   *
   * Sets the `itself` flag, later used by the `respondTo` assertion.
   *
   *     function Foo() {}
   *     Foo.bar = function() {}
   *     Foo.prototype.baz = function() {}
   *
   *     expect(Foo).itself.to.respondTo('bar');
   *     expect(Foo).itself.not.to.respondTo('baz');
   *
   * @name itself
   * @namespace BDD
   * @api public
   */

  Assertion.addProperty('itself', function () {
    flag(this, 'itself', true);
  });

  /**
   * ### .satisfy(method)
   *
   * Asserts that the target passes a given truth test.
   *
   *     expect(1).to.satisfy(function(num) { return num > 0; });
   *
   * @name satisfy
   * @alias satisfies
   * @param {Function} matcher
   * @param {String} message _optional_
   * @namespace BDD
   * @api public
   */

  function satisfy (matcher, msg) {
    if (msg) flag(this, 'message', msg);
    var obj = flag(this, 'object');
    var result = matcher(obj);
    this.assert(
        result
      , 'expected #{this} to satisfy ' + _.objDisplay(matcher)
      , 'expected #{this} to not satisfy' + _.objDisplay(matcher)
      , this.negate ? false : true
      , result
    );
  }

  Assertion.addMethod('satisfy', satisfy);
  Assertion.addMethod('satisfies', satisfy);

  /**
   * ### .closeTo(expected, delta)
   *
   * Asserts that the target is equal `expected`, to within a +/- `delta` range.
   *
   *     expect(1.5).to.be.closeTo(1, 0.5);
   *
   * @name closeTo
   * @alias approximately
   * @param {Number} expected
   * @param {Number} delta
   * @param {String} message _optional_
   * @namespace BDD
   * @api public
   */

  function closeTo(expected, delta, msg) {
    if (msg) flag(this, 'message', msg);
    var obj = flag(this, 'object');

    new Assertion(obj, msg).is.a('number');
    if (_.type(expected) !== 'number' || _.type(delta) !== 'number') {
      throw new Error('the arguments to closeTo or approximately must be numbers');
    }

    this.assert(
        Math.abs(obj - expected) <= delta
      , 'expected #{this} to be close to ' + expected + ' +/- ' + delta
      , 'expected #{this} not to be close to ' + expected + ' +/- ' + delta
    );
  }

  Assertion.addMethod('closeTo', closeTo);
  Assertion.addMethod('approximately', closeTo);

  function isSubsetOf(subset, superset, cmp) {
    return subset.every(function(elem) {
      if (!cmp) return superset.indexOf(elem) !== -1;

      return superset.some(function(elem2) {
        return cmp(elem, elem2);
      });
    })
  }

  /**
   * ### .members(set)
   *
   * Asserts that the target is a superset of `set`,
   * or that the target and `set` have the same strictly-equal (===) members.
   * Alternately, if the `deep` flag is set, set members are compared for deep
   * equality.
   *
   *     expect([1, 2, 3]).to.include.members([3, 2]);
   *     expect([1, 2, 3]).to.not.include.members([3, 2, 8]);
   *
   *     expect([4, 2]).to.have.members([2, 4]);
   *     expect([5, 2]).to.not.have.members([5, 2, 1]);
   *
   *     expect([{ id: 1 }]).to.deep.include.members([{ id: 1 }]);
   *
   * @name members
   * @param {Array} set
   * @param {String} message _optional_
   * @namespace BDD
   * @api public
   */

  Assertion.addMethod('members', function (subset, msg) {
    if (msg) flag(this, 'message', msg);
    var obj = flag(this, 'object');

    new Assertion(obj).to.be.an('array');
    new Assertion(subset).to.be.an('array');

    var cmp = flag(this, 'deep') ? _.eql : undefined;

    if (flag(this, 'contains')) {
      return this.assert(
          isSubsetOf(subset, obj, cmp)
        , 'expected #{this} to be a superset of #{act}'
        , 'expected #{this} to not be a superset of #{act}'
        , obj
        , subset
      );
    }

    this.assert(
        isSubsetOf(obj, subset, cmp) && isSubsetOf(subset, obj, cmp)
        , 'expected #{this} to have the same members as #{act}'
        , 'expected #{this} to not have the same members as #{act}'
        , obj
        , subset
    );
  });

  /**
   * ### .oneOf(list)
   *
   * Assert that a value appears somewhere in the top level of array `list`.
   *
   *     expect('a').to.be.oneOf(['a', 'b', 'c']);
   *     expect(9).to.not.be.oneOf(['z']);
   *     expect([3]).to.not.be.oneOf([1, 2, [3]]);
   *
   *     var three = [3];
   *     // for object-types, contents are not compared
   *     expect(three).to.not.be.oneOf([1, 2, [3]]);
   *     // comparing references works
   *     expect(three).to.be.oneOf([1, 2, three]);
   *
   * @name oneOf
   * @param {Array<*>} list
   * @param {String} message _optional_
   * @namespace BDD
   * @api public
   */

  function oneOf (list, msg) {
    if (msg) flag(this, 'message', msg);
    var expected = flag(this, 'object');
    new Assertion(list).to.be.an('array');

    this.assert(
        list.indexOf(expected) > -1
      , 'expected #{this} to be one of #{exp}'
      , 'expected #{this} to not be one of #{exp}'
      , list
      , expected
    );
  }

  Assertion.addMethod('oneOf', oneOf);


  /**
   * ### .change(function)
   *
   * Asserts that a function changes an object property
   *
   *     var obj = { val: 10 };
   *     var fn = function() { obj.val += 3 };
   *     var noChangeFn = function() { return 'foo' + 'bar'; }
   *     expect(fn).to.change(obj, 'val');
   *     expect(noChangeFn).to.not.change(obj, 'val')
   *
   * @name change
   * @alias changes
   * @alias Change
   * @param {String} object
   * @param {String} property name
   * @param {String} message _optional_
   * @namespace BDD
   * @api public
   */

  function assertChanges (object, prop, msg) {
    if (msg) flag(this, 'message', msg);
    var fn = flag(this, 'object');
    new Assertion(object, msg).to.have.property(prop);
    new Assertion(fn).is.a('function');

    var initial = object[prop];
    fn();

    this.assert(
      initial !== object[prop]
      , 'expected .' + prop + ' to change'
      , 'expected .' + prop + ' to not change'
    );
  }

  Assertion.addChainableMethod('change', assertChanges);
  Assertion.addChainableMethod('changes', assertChanges);

  /**
   * ### .increase(function)
   *
   * Asserts that a function increases an object property
   *
   *     var obj = { val: 10 };
   *     var fn = function() { obj.val = 15 };
   *     expect(fn).to.increase(obj, 'val');
   *
   * @name increase
   * @alias increases
   * @alias Increase
   * @param {String} object
   * @param {String} property name
   * @param {String} message _optional_
   * @namespace BDD
   * @api public
   */

  function assertIncreases (object, prop, msg) {
    if (msg) flag(this, 'message', msg);
    var fn = flag(this, 'object');
    new Assertion(object, msg).to.have.property(prop);
    new Assertion(fn).is.a('function');

    var initial = object[prop];
    fn();

    this.assert(
      object[prop] - initial > 0
      , 'expected .' + prop + ' to increase'
      , 'expected .' + prop + ' to not increase'
    );
  }

  Assertion.addChainableMethod('increase', assertIncreases);
  Assertion.addChainableMethod('increases', assertIncreases);

  /**
   * ### .decrease(function)
   *
   * Asserts that a function decreases an object property
   *
   *     var obj = { val: 10 };
   *     var fn = function() { obj.val = 5 };
   *     expect(fn).to.decrease(obj, 'val');
   *
   * @name decrease
   * @alias decreases
   * @alias Decrease
   * @param {String} object
   * @param {String} property name
   * @param {String} message _optional_
   * @namespace BDD
   * @api public
   */

  function assertDecreases (object, prop, msg) {
    if (msg) flag(this, 'message', msg);
    var fn = flag(this, 'object');
    new Assertion(object, msg).to.have.property(prop);
    new Assertion(fn).is.a('function');

    var initial = object[prop];
    fn();

    this.assert(
      object[prop] - initial < 0
      , 'expected .' + prop + ' to decrease'
      , 'expected .' + prop + ' to not decrease'
    );
  }

  Assertion.addChainableMethod('decrease', assertDecreases);
  Assertion.addChainableMethod('decreases', assertDecreases);

  /**
   * ### .extensible
   *
   * Asserts that the target is extensible (can have new properties added to
   * it).
   *
   *     var nonExtensibleObject = Object.preventExtensions({});
   *     var sealedObject = Object.seal({});
   *     var frozenObject = Object.freeze({});
   *
   *     expect({}).to.be.extensible;
   *     expect(nonExtensibleObject).to.not.be.extensible;
   *     expect(sealedObject).to.not.be.extensible;
   *     expect(frozenObject).to.not.be.extensible;
   *
   * @name extensible
   * @namespace BDD
   * @api public
   */

  Assertion.addProperty('extensible', function() {
    var obj = flag(this, 'object');

    // In ES5, if the argument to this method is not an object (a primitive), then it will cause a TypeError.
    // In ES6, a non-object argument will be treated as if it was a non-extensible ordinary object, simply return false.
    // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isExtensible
    // The following provides ES6 behavior when a TypeError is thrown under ES5.

    var isExtensible;

    try {
      isExtensible = Object.isExtensible(obj);
    } catch (err) {
      if (err instanceof TypeError) isExtensible = false;
      else throw err;
    }

    this.assert(
      isExtensible
      , 'expected #{this} to be extensible'
      , 'expected #{this} to not be extensible'
    );
  });

  /**
   * ### .sealed
   *
   * Asserts that the target is sealed (cannot have new properties added to it
   * and its existing properties cannot be removed).
   *
   *     var sealedObject = Object.seal({});
   *     var frozenObject = Object.freeze({});
   *
   *     expect(sealedObject).to.be.sealed;
   *     expect(frozenObject).to.be.sealed;
   *     expect({}).to.not.be.sealed;
   *
   * @name sealed
   * @namespace BDD
   * @api public
   */

  Assertion.addProperty('sealed', function() {
    var obj = flag(this, 'object');

    // In ES5, if the argument to this method is not an object (a primitive), then it will cause a TypeError.
    // In ES6, a non-object argument will be treated as if it was a sealed ordinary object, simply return true.
    // See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isSealed
    // The following provides ES6 behavior when a TypeError is thrown under ES5.

    var isSealed;

    try {
      isSealed = Object.isSealed(obj);
    } catch (err) {
      if (err instanceof TypeError) isSealed = true;
      else throw err;
    }

    this.assert(
      isSealed
      , 'expected #{this} to be sealed'
      , 'expected #{this} to not be sealed'
    );
  });

  /**
   * ### .frozen
   *
   * Asserts that the target is frozen (cannot have new properties added to it
   * and its existing properties cannot be modified).
   *
   *     var frozenObject = Object.freeze({});
   *
   *     expect(frozenObject).to.be.frozen;
   *     expect({}).to.not.be.frozen;
   *
   * @name frozen
   * @namespace BDD
   * @api public
   */

  Assertion.addProperty('frozen', function() {
    var obj = flag(this, 'object');

    // In ES5, if the argument to this method is not an object (a primitive), then it will cause a TypeError.
    // In ES6, a non-object argument will be treated as if it was a frozen ordinary object, simply return true.
    // See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isFrozen
    // The following provides ES6 behavior when a TypeError is thrown under ES5.

    var isFrozen;

    try {
      isFrozen = Object.isFrozen(obj);
    } catch (err) {
      if (err instanceof TypeError) isFrozen = true;
      else throw err;
    }

    this.assert(
      isFrozen
      , 'expected #{this} to be frozen'
      , 'expected #{this} to not be frozen'
    );
  });
};

},{}],6:[function(require,module,exports){
/*!
 * chai
 * Copyright(c) 2011-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */


module.exports = function (chai, util) {

  /*!
   * Chai dependencies.
   */

  var Assertion = chai.Assertion
    , flag = util.flag;

  /*!
   * Module export.
   */

  /**
   * ### assert(expression, message)
   *
   * Write your own test expressions.
   *
   *     assert('foo' !== 'bar', 'foo is not bar');
   *     assert(Array.isArray([]), 'empty arrays are arrays');
   *
   * @param {Mixed} expression to test for truthiness
   * @param {String} message to display on error
   * @name assert
   * @namespace Assert
   * @api public
   */

  var assert = chai.assert = function (express, errmsg) {
    var test = new Assertion(null, null, chai.assert);
    test.assert(
        express
      , errmsg
      , '[ negation message unavailable ]'
    );
  };

  /**
   * ### .fail(actual, expected, [message], [operator])
   *
   * Throw a failure. Node.js `assert` module-compatible.
   *
   * @name fail
   * @param {Mixed} actual
   * @param {Mixed} expected
   * @param {String} message
   * @param {String} operator
   * @namespace Assert
   * @api public
   */

  assert.fail = function (actual, expected, message, operator) {
    message = message || 'assert.fail()';
    throw new chai.AssertionError(message, {
        actual: actual
      , expected: expected
      , operator: operator
    }, assert.fail);
  };

  /**
   * ### .isOk(object, [message])
   *
   * Asserts that `object` is truthy.
   *
   *     assert.isOk('everything', 'everything is ok');
   *     assert.isOk(false, 'this will fail');
   *
   * @name isOk
   * @alias ok
   * @param {Mixed} object to test
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isOk = function (val, msg) {
    new Assertion(val, msg).is.ok;
  };

  /**
   * ### .isNotOk(object, [message])
   *
   * Asserts that `object` is falsy.
   *
   *     assert.isNotOk('everything', 'this will fail');
   *     assert.isNotOk(false, 'this will pass');
   *
   * @name isNotOk
   * @alias notOk
   * @param {Mixed} object to test
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isNotOk = function (val, msg) {
    new Assertion(val, msg).is.not.ok;
  };

  /**
   * ### .equal(actual, expected, [message])
   *
   * Asserts non-strict equality (`==`) of `actual` and `expected`.
   *
   *     assert.equal(3, '3', '== coerces values to strings');
   *
   * @name equal
   * @param {Mixed} actual
   * @param {Mixed} expected
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.equal = function (act, exp, msg) {
    var test = new Assertion(act, msg, assert.equal);

    test.assert(
        exp == flag(test, 'object')
      , 'expected #{this} to equal #{exp}'
      , 'expected #{this} to not equal #{act}'
      , exp
      , act
    );
  };

  /**
   * ### .notEqual(actual, expected, [message])
   *
   * Asserts non-strict inequality (`!=`) of `actual` and `expected`.
   *
   *     assert.notEqual(3, 4, 'these numbers are not equal');
   *
   * @name notEqual
   * @param {Mixed} actual
   * @param {Mixed} expected
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.notEqual = function (act, exp, msg) {
    var test = new Assertion(act, msg, assert.notEqual);

    test.assert(
        exp != flag(test, 'object')
      , 'expected #{this} to not equal #{exp}'
      , 'expected #{this} to equal #{act}'
      , exp
      , act
    );
  };

  /**
   * ### .strictEqual(actual, expected, [message])
   *
   * Asserts strict equality (`===`) of `actual` and `expected`.
   *
   *     assert.strictEqual(true, true, 'these booleans are strictly equal');
   *
   * @name strictEqual
   * @param {Mixed} actual
   * @param {Mixed} expected
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.strictEqual = function (act, exp, msg) {
    new Assertion(act, msg).to.equal(exp);
  };

  /**
   * ### .notStrictEqual(actual, expected, [message])
   *
   * Asserts strict inequality (`!==`) of `actual` and `expected`.
   *
   *     assert.notStrictEqual(3, '3', 'no coercion for strict equality');
   *
   * @name notStrictEqual
   * @param {Mixed} actual
   * @param {Mixed} expected
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.notStrictEqual = function (act, exp, msg) {
    new Assertion(act, msg).to.not.equal(exp);
  };

  /**
   * ### .deepEqual(actual, expected, [message])
   *
   * Asserts that `actual` is deeply equal to `expected`.
   *
   *     assert.deepEqual({ tea: 'green' }, { tea: 'green' });
   *
   * @name deepEqual
   * @param {Mixed} actual
   * @param {Mixed} expected
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.deepEqual = function (act, exp, msg) {
    new Assertion(act, msg).to.eql(exp);
  };

  /**
   * ### .notDeepEqual(actual, expected, [message])
   *
   * Assert that `actual` is not deeply equal to `expected`.
   *
   *     assert.notDeepEqual({ tea: 'green' }, { tea: 'jasmine' });
   *
   * @name notDeepEqual
   * @param {Mixed} actual
   * @param {Mixed} expected
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.notDeepEqual = function (act, exp, msg) {
    new Assertion(act, msg).to.not.eql(exp);
  };

   /**
   * ### .isAbove(valueToCheck, valueToBeAbove, [message])
   *
   * Asserts `valueToCheck` is strictly greater than (>) `valueToBeAbove`
   *
   *     assert.isAbove(5, 2, '5 is strictly greater than 2');
   *
   * @name isAbove
   * @param {Mixed} valueToCheck
   * @param {Mixed} valueToBeAbove
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isAbove = function (val, abv, msg) {
    new Assertion(val, msg).to.be.above(abv);
  };

   /**
   * ### .isAtLeast(valueToCheck, valueToBeAtLeast, [message])
   *
   * Asserts `valueToCheck` is greater than or equal to (>=) `valueToBeAtLeast`
   *
   *     assert.isAtLeast(5, 2, '5 is greater or equal to 2');
   *     assert.isAtLeast(3, 3, '3 is greater or equal to 3');
   *
   * @name isAtLeast
   * @param {Mixed} valueToCheck
   * @param {Mixed} valueToBeAtLeast
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isAtLeast = function (val, atlst, msg) {
    new Assertion(val, msg).to.be.least(atlst);
  };

   /**
   * ### .isBelow(valueToCheck, valueToBeBelow, [message])
   *
   * Asserts `valueToCheck` is strictly less than (<) `valueToBeBelow`
   *
   *     assert.isBelow(3, 6, '3 is strictly less than 6');
   *
   * @name isBelow
   * @param {Mixed} valueToCheck
   * @param {Mixed} valueToBeBelow
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isBelow = function (val, blw, msg) {
    new Assertion(val, msg).to.be.below(blw);
  };

   /**
   * ### .isAtMost(valueToCheck, valueToBeAtMost, [message])
   *
   * Asserts `valueToCheck` is less than or equal to (<=) `valueToBeAtMost`
   *
   *     assert.isAtMost(3, 6, '3 is less than or equal to 6');
   *     assert.isAtMost(4, 4, '4 is less than or equal to 4');
   *
   * @name isAtMost
   * @param {Mixed} valueToCheck
   * @param {Mixed} valueToBeAtMost
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isAtMost = function (val, atmst, msg) {
    new Assertion(val, msg).to.be.most(atmst);
  };

  /**
   * ### .isTrue(value, [message])
   *
   * Asserts that `value` is true.
   *
   *     var teaServed = true;
   *     assert.isTrue(teaServed, 'the tea has been served');
   *
   * @name isTrue
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isTrue = function (val, msg) {
    new Assertion(val, msg).is['true'];
  };

  /**
   * ### .isNotTrue(value, [message])
   *
   * Asserts that `value` is not true.
   *
   *     var tea = 'tasty chai';
   *     assert.isNotTrue(tea, 'great, time for tea!');
   *
   * @name isNotTrue
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isNotTrue = function (val, msg) {
    new Assertion(val, msg).to.not.equal(true);
  };

  /**
   * ### .isFalse(value, [message])
   *
   * Asserts that `value` is false.
   *
   *     var teaServed = false;
   *     assert.isFalse(teaServed, 'no tea yet? hmm...');
   *
   * @name isFalse
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isFalse = function (val, msg) {
    new Assertion(val, msg).is['false'];
  };

  /**
   * ### .isNotFalse(value, [message])
   *
   * Asserts that `value` is not false.
   *
   *     var tea = 'tasty chai';
   *     assert.isNotFalse(tea, 'great, time for tea!');
   *
   * @name isNotFalse
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isNotFalse = function (val, msg) {
    new Assertion(val, msg).to.not.equal(false);
  };

  /**
   * ### .isNull(value, [message])
   *
   * Asserts that `value` is null.
   *
   *     assert.isNull(err, 'there was no error');
   *
   * @name isNull
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isNull = function (val, msg) {
    new Assertion(val, msg).to.equal(null);
  };

  /**
   * ### .isNotNull(value, [message])
   *
   * Asserts that `value` is not null.
   *
   *     var tea = 'tasty chai';
   *     assert.isNotNull(tea, 'great, time for tea!');
   *
   * @name isNotNull
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isNotNull = function (val, msg) {
    new Assertion(val, msg).to.not.equal(null);
  };

  /**
   * ### .isNaN
   * Asserts that value is NaN
   *
   *    assert.isNaN('foo', 'foo is NaN');
   *
   * @name isNaN
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isNaN = function (val, msg) {
    new Assertion(val, msg).to.be.NaN;
  };

  /**
   * ### .isNotNaN
   * Asserts that value is not NaN
   *
   *    assert.isNotNaN(4, '4 is not NaN');
   *
   * @name isNotNaN
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */
  assert.isNotNaN = function (val, msg) {
    new Assertion(val, msg).not.to.be.NaN;
  };

  /**
   * ### .isUndefined(value, [message])
   *
   * Asserts that `value` is `undefined`.
   *
   *     var tea;
   *     assert.isUndefined(tea, 'no tea defined');
   *
   * @name isUndefined
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isUndefined = function (val, msg) {
    new Assertion(val, msg).to.equal(undefined);
  };

  /**
   * ### .isDefined(value, [message])
   *
   * Asserts that `value` is not `undefined`.
   *
   *     var tea = 'cup of chai';
   *     assert.isDefined(tea, 'tea has been defined');
   *
   * @name isDefined
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isDefined = function (val, msg) {
    new Assertion(val, msg).to.not.equal(undefined);
  };

  /**
   * ### .isFunction(value, [message])
   *
   * Asserts that `value` is a function.
   *
   *     function serveTea() { return 'cup of tea'; };
   *     assert.isFunction(serveTea, 'great, we can have tea now');
   *
   * @name isFunction
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isFunction = function (val, msg) {
    new Assertion(val, msg).to.be.a('function');
  };

  /**
   * ### .isNotFunction(value, [message])
   *
   * Asserts that `value` is _not_ a function.
   *
   *     var serveTea = [ 'heat', 'pour', 'sip' ];
   *     assert.isNotFunction(serveTea, 'great, we have listed the steps');
   *
   * @name isNotFunction
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isNotFunction = function (val, msg) {
    new Assertion(val, msg).to.not.be.a('function');
  };

  /**
   * ### .isObject(value, [message])
   *
   * Asserts that `value` is an object of type 'Object' (as revealed by `Object.prototype.toString`).
   * _The assertion does not match subclassed objects._
   *
   *     var selection = { name: 'Chai', serve: 'with spices' };
   *     assert.isObject(selection, 'tea selection is an object');
   *
   * @name isObject
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isObject = function (val, msg) {
    new Assertion(val, msg).to.be.a('object');
  };

  /**
   * ### .isNotObject(value, [message])
   *
   * Asserts that `value` is _not_ an object of type 'Object' (as revealed by `Object.prototype.toString`).
   *
   *     var selection = 'chai'
   *     assert.isNotObject(selection, 'tea selection is not an object');
   *     assert.isNotObject(null, 'null is not an object');
   *
   * @name isNotObject
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isNotObject = function (val, msg) {
    new Assertion(val, msg).to.not.be.a('object');
  };

  /**
   * ### .isArray(value, [message])
   *
   * Asserts that `value` is an array.
   *
   *     var menu = [ 'green', 'chai', 'oolong' ];
   *     assert.isArray(menu, 'what kind of tea do we want?');
   *
   * @name isArray
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isArray = function (val, msg) {
    new Assertion(val, msg).to.be.an('array');
  };

  /**
   * ### .isNotArray(value, [message])
   *
   * Asserts that `value` is _not_ an array.
   *
   *     var menu = 'green|chai|oolong';
   *     assert.isNotArray(menu, 'what kind of tea do we want?');
   *
   * @name isNotArray
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isNotArray = function (val, msg) {
    new Assertion(val, msg).to.not.be.an('array');
  };

  /**
   * ### .isString(value, [message])
   *
   * Asserts that `value` is a string.
   *
   *     var teaOrder = 'chai';
   *     assert.isString(teaOrder, 'order placed');
   *
   * @name isString
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isString = function (val, msg) {
    new Assertion(val, msg).to.be.a('string');
  };

  /**
   * ### .isNotString(value, [message])
   *
   * Asserts that `value` is _not_ a string.
   *
   *     var teaOrder = 4;
   *     assert.isNotString(teaOrder, 'order placed');
   *
   * @name isNotString
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isNotString = function (val, msg) {
    new Assertion(val, msg).to.not.be.a('string');
  };

  /**
   * ### .isNumber(value, [message])
   *
   * Asserts that `value` is a number.
   *
   *     var cups = 2;
   *     assert.isNumber(cups, 'how many cups');
   *
   * @name isNumber
   * @param {Number} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isNumber = function (val, msg) {
    new Assertion(val, msg).to.be.a('number');
  };

  /**
   * ### .isNotNumber(value, [message])
   *
   * Asserts that `value` is _not_ a number.
   *
   *     var cups = '2 cups please';
   *     assert.isNotNumber(cups, 'how many cups');
   *
   * @name isNotNumber
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isNotNumber = function (val, msg) {
    new Assertion(val, msg).to.not.be.a('number');
  };

  /**
   * ### .isBoolean(value, [message])
   *
   * Asserts that `value` is a boolean.
   *
   *     var teaReady = true
   *       , teaServed = false;
   *
   *     assert.isBoolean(teaReady, 'is the tea ready');
   *     assert.isBoolean(teaServed, 'has tea been served');
   *
   * @name isBoolean
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isBoolean = function (val, msg) {
    new Assertion(val, msg).to.be.a('boolean');
  };

  /**
   * ### .isNotBoolean(value, [message])
   *
   * Asserts that `value` is _not_ a boolean.
   *
   *     var teaReady = 'yep'
   *       , teaServed = 'nope';
   *
   *     assert.isNotBoolean(teaReady, 'is the tea ready');
   *     assert.isNotBoolean(teaServed, 'has tea been served');
   *
   * @name isNotBoolean
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.isNotBoolean = function (val, msg) {
    new Assertion(val, msg).to.not.be.a('boolean');
  };

  /**
   * ### .typeOf(value, name, [message])
   *
   * Asserts that `value`'s type is `name`, as determined by
   * `Object.prototype.toString`.
   *
   *     assert.typeOf({ tea: 'chai' }, 'object', 'we have an object');
   *     assert.typeOf(['chai', 'jasmine'], 'array', 'we have an array');
   *     assert.typeOf('tea', 'string', 'we have a string');
   *     assert.typeOf(/tea/, 'regexp', 'we have a regular expression');
   *     assert.typeOf(null, 'null', 'we have a null');
   *     assert.typeOf(undefined, 'undefined', 'we have an undefined');
   *
   * @name typeOf
   * @param {Mixed} value
   * @param {String} name
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.typeOf = function (val, type, msg) {
    new Assertion(val, msg).to.be.a(type);
  };

  /**
   * ### .notTypeOf(value, name, [message])
   *
   * Asserts that `value`'s type is _not_ `name`, as determined by
   * `Object.prototype.toString`.
   *
   *     assert.notTypeOf('tea', 'number', 'strings are not numbers');
   *
   * @name notTypeOf
   * @param {Mixed} value
   * @param {String} typeof name
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.notTypeOf = function (val, type, msg) {
    new Assertion(val, msg).to.not.be.a(type);
  };

  /**
   * ### .instanceOf(object, constructor, [message])
   *
   * Asserts that `value` is an instance of `constructor`.
   *
   *     var Tea = function (name) { this.name = name; }
   *       , chai = new Tea('chai');
   *
   *     assert.instanceOf(chai, Tea, 'chai is an instance of tea');
   *
   * @name instanceOf
   * @param {Object} object
   * @param {Constructor} constructor
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.instanceOf = function (val, type, msg) {
    new Assertion(val, msg).to.be.instanceOf(type);
  };

  /**
   * ### .notInstanceOf(object, constructor, [message])
   *
   * Asserts `value` is not an instance of `constructor`.
   *
   *     var Tea = function (name) { this.name = name; }
   *       , chai = new String('chai');
   *
   *     assert.notInstanceOf(chai, Tea, 'chai is not an instance of tea');
   *
   * @name notInstanceOf
   * @param {Object} object
   * @param {Constructor} constructor
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.notInstanceOf = function (val, type, msg) {
    new Assertion(val, msg).to.not.be.instanceOf(type);
  };

  /**
   * ### .include(haystack, needle, [message])
   *
   * Asserts that `haystack` includes `needle`. Works
   * for strings and arrays.
   *
   *     assert.include('foobar', 'bar', 'foobar contains string "bar"');
   *     assert.include([ 1, 2, 3 ], 3, 'array contains value');
   *
   * @name include
   * @param {Array|String} haystack
   * @param {Mixed} needle
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.include = function (exp, inc, msg) {
    new Assertion(exp, msg, assert.include).include(inc);
  };

  /**
   * ### .notInclude(haystack, needle, [message])
   *
   * Asserts that `haystack` does not include `needle`. Works
   * for strings and arrays.
   *
   *     assert.notInclude('foobar', 'baz', 'string not include substring');
   *     assert.notInclude([ 1, 2, 3 ], 4, 'array not include contain value');
   *
   * @name notInclude
   * @param {Array|String} haystack
   * @param {Mixed} needle
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.notInclude = function (exp, inc, msg) {
    new Assertion(exp, msg, assert.notInclude).not.include(inc);
  };

  /**
   * ### .match(value, regexp, [message])
   *
   * Asserts that `value` matches the regular expression `regexp`.
   *
   *     assert.match('foobar', /^foo/, 'regexp matches');
   *
   * @name match
   * @param {Mixed} value
   * @param {RegExp} regexp
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.match = function (exp, re, msg) {
    new Assertion(exp, msg).to.match(re);
  };

  /**
   * ### .notMatch(value, regexp, [message])
   *
   * Asserts that `value` does not match the regular expression `regexp`.
   *
   *     assert.notMatch('foobar', /^foo/, 'regexp does not match');
   *
   * @name notMatch
   * @param {Mixed} value
   * @param {RegExp} regexp
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.notMatch = function (exp, re, msg) {
    new Assertion(exp, msg).to.not.match(re);
  };

  /**
   * ### .property(object, property, [message])
   *
   * Asserts that `object` has a property named by `property`.
   *
   *     assert.property({ tea: { green: 'matcha' }}, 'tea');
   *
   * @name property
   * @param {Object} object
   * @param {String} property
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.property = function (obj, prop, msg) {
    new Assertion(obj, msg).to.have.property(prop);
  };

  /**
   * ### .notProperty(object, property, [message])
   *
   * Asserts that `object` does _not_ have a property named by `property`.
   *
   *     assert.notProperty({ tea: { green: 'matcha' }}, 'coffee');
   *
   * @name notProperty
   * @param {Object} object
   * @param {String} property
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.notProperty = function (obj, prop, msg) {
    new Assertion(obj, msg).to.not.have.property(prop);
  };

  /**
   * ### .deepProperty(object, property, [message])
   *
   * Asserts that `object` has a property named by `property`, which can be a
   * string using dot- and bracket-notation for deep reference.
   *
   *     assert.deepProperty({ tea: { green: 'matcha' }}, 'tea.green');
   *
   * @name deepProperty
   * @param {Object} object
   * @param {String} property
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.deepProperty = function (obj, prop, msg) {
    new Assertion(obj, msg).to.have.deep.property(prop);
  };

  /**
   * ### .notDeepProperty(object, property, [message])
   *
   * Asserts that `object` does _not_ have a property named by `property`, which
   * can be a string using dot- and bracket-notation for deep reference.
   *
   *     assert.notDeepProperty({ tea: { green: 'matcha' }}, 'tea.oolong');
   *
   * @name notDeepProperty
   * @param {Object} object
   * @param {String} property
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.notDeepProperty = function (obj, prop, msg) {
    new Assertion(obj, msg).to.not.have.deep.property(prop);
  };

  /**
   * ### .propertyVal(object, property, value, [message])
   *
   * Asserts that `object` has a property named by `property` with value given
   * by `value`.
   *
   *     assert.propertyVal({ tea: 'is good' }, 'tea', 'is good');
   *
   * @name propertyVal
   * @param {Object} object
   * @param {String} property
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.propertyVal = function (obj, prop, val, msg) {
    new Assertion(obj, msg).to.have.property(prop, val);
  };

  /**
   * ### .propertyNotVal(object, property, value, [message])
   *
   * Asserts that `object` has a property named by `property`, but with a value
   * different from that given by `value`.
   *
   *     assert.propertyNotVal({ tea: 'is good' }, 'tea', 'is bad');
   *
   * @name propertyNotVal
   * @param {Object} object
   * @param {String} property
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.propertyNotVal = function (obj, prop, val, msg) {
    new Assertion(obj, msg).to.not.have.property(prop, val);
  };

  /**
   * ### .deepPropertyVal(object, property, value, [message])
   *
   * Asserts that `object` has a property named by `property` with value given
   * by `value`. `property` can use dot- and bracket-notation for deep
   * reference.
   *
   *     assert.deepPropertyVal({ tea: { green: 'matcha' }}, 'tea.green', 'matcha');
   *
   * @name deepPropertyVal
   * @param {Object} object
   * @param {String} property
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.deepPropertyVal = function (obj, prop, val, msg) {
    new Assertion(obj, msg).to.have.deep.property(prop, val);
  };

  /**
   * ### .deepPropertyNotVal(object, property, value, [message])
   *
   * Asserts that `object` has a property named by `property`, but with a value
   * different from that given by `value`. `property` can use dot- and
   * bracket-notation for deep reference.
   *
   *     assert.deepPropertyNotVal({ tea: { green: 'matcha' }}, 'tea.green', 'konacha');
   *
   * @name deepPropertyNotVal
   * @param {Object} object
   * @param {String} property
   * @param {Mixed} value
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.deepPropertyNotVal = function (obj, prop, val, msg) {
    new Assertion(obj, msg).to.not.have.deep.property(prop, val);
  };

  /**
   * ### .lengthOf(object, length, [message])
   *
   * Asserts that `object` has a `length` property with the expected value.
   *
   *     assert.lengthOf([1,2,3], 3, 'array has length of 3');
   *     assert.lengthOf('foobar', 6, 'string has length of 6');
   *
   * @name lengthOf
   * @param {Mixed} object
   * @param {Number} length
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.lengthOf = function (exp, len, msg) {
    new Assertion(exp, msg).to.have.length(len);
  };

  /**
   * ### .throws(function, [constructor/string/regexp], [string/regexp], [message])
   *
   * Asserts that `function` will throw an error that is an instance of
   * `constructor`, or alternately that it will throw an error with message
   * matching `regexp`.
   *
   *     assert.throws(fn, 'function throws a reference error');
   *     assert.throws(fn, /function throws a reference error/);
   *     assert.throws(fn, ReferenceError);
   *     assert.throws(fn, ReferenceError, 'function throws a reference error');
   *     assert.throws(fn, ReferenceError, /function throws a reference error/);
   *
   * @name throws
   * @alias throw
   * @alias Throw
   * @param {Function} function
   * @param {ErrorConstructor} constructor
   * @param {RegExp} regexp
   * @param {String} message
   * @see https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Error#Error_types
   * @namespace Assert
   * @api public
   */

  assert.throws = function (fn, errt, errs, msg) {
    if ('string' === typeof errt || errt instanceof RegExp) {
      errs = errt;
      errt = null;
    }

    var assertErr = new Assertion(fn, msg).to.throw(errt, errs);
    return flag(assertErr, 'object');
  };

  /**
   * ### .doesNotThrow(function, [constructor/regexp], [message])
   *
   * Asserts that `function` will _not_ throw an error that is an instance of
   * `constructor`, or alternately that it will not throw an error with message
   * matching `regexp`.
   *
   *     assert.doesNotThrow(fn, Error, 'function does not throw');
   *
   * @name doesNotThrow
   * @param {Function} function
   * @param {ErrorConstructor} constructor
   * @param {RegExp} regexp
   * @param {String} message
   * @see https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Error#Error_types
   * @namespace Assert
   * @api public
   */

  assert.doesNotThrow = function (fn, type, msg) {
    if ('string' === typeof type) {
      msg = type;
      type = null;
    }

    new Assertion(fn, msg).to.not.Throw(type);
  };

  /**
   * ### .operator(val1, operator, val2, [message])
   *
   * Compares two values using `operator`.
   *
   *     assert.operator(1, '<', 2, 'everything is ok');
   *     assert.operator(1, '>', 2, 'this will fail');
   *
   * @name operator
   * @param {Mixed} val1
   * @param {String} operator
   * @param {Mixed} val2
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.operator = function (val, operator, val2, msg) {
    var ok;
    switch(operator) {
      case '==':
        ok = val == val2;
        break;
      case '===':
        ok = val === val2;
        break;
      case '>':
        ok = val > val2;
        break;
      case '>=':
        ok = val >= val2;
        break;
      case '<':
        ok = val < val2;
        break;
      case '<=':
        ok = val <= val2;
        break;
      case '!=':
        ok = val != val2;
        break;
      case '!==':
        ok = val !== val2;
        break;
      default:
        throw new Error('Invalid operator "' + operator + '"');
    }
    var test = new Assertion(ok, msg);
    test.assert(
        true === flag(test, 'object')
      , 'expected ' + util.inspect(val) + ' to be ' + operator + ' ' + util.inspect(val2)
      , 'expected ' + util.inspect(val) + ' to not be ' + operator + ' ' + util.inspect(val2) );
  };

  /**
   * ### .closeTo(actual, expected, delta, [message])
   *
   * Asserts that the target is equal `expected`, to within a +/- `delta` range.
   *
   *     assert.closeTo(1.5, 1, 0.5, 'numbers are close');
   *
   * @name closeTo
   * @param {Number} actual
   * @param {Number} expected
   * @param {Number} delta
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.closeTo = function (act, exp, delta, msg) {
    new Assertion(act, msg).to.be.closeTo(exp, delta);
  };

  /**
   * ### .approximately(actual, expected, delta, [message])
   *
   * Asserts that the target is equal `expected`, to within a +/- `delta` range.
   *
   *     assert.approximately(1.5, 1, 0.5, 'numbers are close');
   *
   * @name approximately
   * @param {Number} actual
   * @param {Number} expected
   * @param {Number} delta
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.approximately = function (act, exp, delta, msg) {
    new Assertion(act, msg).to.be.approximately(exp, delta);
  };

  /**
   * ### .sameMembers(set1, set2, [message])
   *
   * Asserts that `set1` and `set2` have the same members.
   * Order is not taken into account.
   *
   *     assert.sameMembers([ 1, 2, 3 ], [ 2, 1, 3 ], 'same members');
   *
   * @name sameMembers
   * @param {Array} set1
   * @param {Array} set2
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.sameMembers = function (set1, set2, msg) {
    new Assertion(set1, msg).to.have.same.members(set2);
  }

  /**
   * ### .sameDeepMembers(set1, set2, [message])
   *
   * Asserts that `set1` and `set2` have the same members - using a deep equality checking.
   * Order is not taken into account.
   *
   *     assert.sameDeepMembers([ {b: 3}, {a: 2}, {c: 5} ], [ {c: 5}, {b: 3}, {a: 2} ], 'same deep members');
   *
   * @name sameDeepMembers
   * @param {Array} set1
   * @param {Array} set2
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.sameDeepMembers = function (set1, set2, msg) {
    new Assertion(set1, msg).to.have.same.deep.members(set2);
  }

  /**
   * ### .includeMembers(superset, subset, [message])
   *
   * Asserts that `subset` is included in `superset`.
   * Order is not taken into account.
   *
   *     assert.includeMembers([ 1, 2, 3 ], [ 2, 1 ], 'include members');
   *
   * @name includeMembers
   * @param {Array} superset
   * @param {Array} subset
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.includeMembers = function (superset, subset, msg) {
    new Assertion(superset, msg).to.include.members(subset);
  }

  /**
   * ### .includeDeepMembers(superset, subset, [message])
   *
   * Asserts that `subset` is included in `superset` - using deep equality checking.
   * Order is not taken into account.
   * Duplicates are ignored.
   *
   *     assert.includeDeepMembers([ {a: 1}, {b: 2}, {c: 3} ], [ {b: 2}, {a: 1}, {b: 2} ], 'include deep members');
   *
   * @name includeDeepMembers
   * @param {Array} superset
   * @param {Array} subset
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.includeDeepMembers = function (superset, subset, msg) {
    new Assertion(superset, msg).to.include.deep.members(subset);
  }

  /**
   * ### .oneOf(inList, list, [message])
   *
   * Asserts that non-object, non-array value `inList` appears in the flat array `list`.
   *
   *     assert.oneOf(1, [ 2, 1 ], 'Not found in list');
   *
   * @name oneOf
   * @param {*} inList
   * @param {Array<*>} list
   * @param {String} message
   * @namespace Assert
   * @api public
   */

  assert.oneOf = function (inList, list, msg) {
    new Assertion(inList, msg).to.be.oneOf(list);
  }

   /**
   * ### .changes(function, object, property)
   *
   * Asserts that a function changes the value of a property
   *
   *     var obj = { val: 10 };
   *     var fn = function() { obj.val = 22 };
   *     assert.changes(fn, obj, 'val');
   *
   * @name changes
   * @param {Function} modifier function
   * @param {Object} object
   * @param {String} property name
   * @param {String} message _optional_
   * @namespace Assert
   * @api public
   */

  assert.changes = function (fn, obj, prop) {
    new Assertion(fn).to.change(obj, prop);
  }

   /**
   * ### .doesNotChange(function, object, property)
   *
   * Asserts that a function does not changes the value of a property
   *
   *     var obj = { val: 10 };
   *     var fn = function() { console.log('foo'); };
   *     assert.doesNotChange(fn, obj, 'val');
   *
   * @name doesNotChange
   * @param {Function} modifier function
   * @param {Object} object
   * @param {String} property name
   * @param {String} message _optional_
   * @namespace Assert
   * @api public
   */

  assert.doesNotChange = function (fn, obj, prop) {
    new Assertion(fn).to.not.change(obj, prop);
  }

   /**
   * ### .increases(function, object, property)
   *
   * Asserts that a function increases an object property
   *
   *     var obj = { val: 10 };
   *     var fn = function() { obj.val = 13 };
   *     assert.increases(fn, obj, 'val');
   *
   * @name increases
   * @param {Function} modifier function
   * @param {Object} object
   * @param {String} property name
   * @param {String} message _optional_
   * @namespace Assert
   * @api public
   */

  assert.increases = function (fn, obj, prop) {
    new Assertion(fn).to.increase(obj, prop);
  }

   /**
   * ### .doesNotIncrease(function, object, property)
   *
   * Asserts that a function does not increase object property
   *
   *     var obj = { val: 10 };
   *     var fn = function() { obj.val = 8 };
   *     assert.doesNotIncrease(fn, obj, 'val');
   *
   * @name doesNotIncrease
   * @param {Function} modifier function
   * @param {Object} object
   * @param {String} property name
   * @param {String} message _optional_
   * @namespace Assert
   * @api public
   */

  assert.doesNotIncrease = function (fn, obj, prop) {
    new Assertion(fn).to.not.increase(obj, prop);
  }

   /**
   * ### .decreases(function, object, property)
   *
   * Asserts that a function decreases an object property
   *
   *     var obj = { val: 10 };
   *     var fn = function() { obj.val = 5 };
   *     assert.decreases(fn, obj, 'val');
   *
   * @name decreases
   * @param {Function} modifier function
   * @param {Object} object
   * @param {String} property name
   * @param {String} message _optional_
   * @namespace Assert
   * @api public
   */

  assert.decreases = function (fn, obj, prop) {
    new Assertion(fn).to.decrease(obj, prop);
  }

   /**
   * ### .doesNotDecrease(function, object, property)
   *
   * Asserts that a function does not decreases an object property
   *
   *     var obj = { val: 10 };
   *     var fn = function() { obj.val = 15 };
   *     assert.doesNotDecrease(fn, obj, 'val');
   *
   * @name doesNotDecrease
   * @param {Function} modifier function
   * @param {Object} object
   * @param {String} property name
   * @param {String} message _optional_
   * @namespace Assert
   * @api public
   */

  assert.doesNotDecrease = function (fn, obj, prop) {
    new Assertion(fn).to.not.decrease(obj, prop);
  }

  /*!
   * ### .ifError(object)
   *
   * Asserts if value is not a false value, and throws if it is a true value.
   * This is added to allow for chai to be a drop-in replacement for Node's
   * assert class.
   *
   *     var err = new Error('I am a custom error');
   *     assert.ifError(err); // Rethrows err!
   *
   * @name ifError
   * @param {Object} object
   * @namespace Assert
   * @api public
   */

  assert.ifError = function (val) {
    if (val) {
      throw(val);
    }
  };

  /**
   * ### .isExtensible(object)
   *
   * Asserts that `object` is extensible (can have new properties added to it).
   *
   *     assert.isExtensible({});
   *
   * @name isExtensible
   * @alias extensible
   * @param {Object} object
   * @param {String} message _optional_
   * @namespace Assert
   * @api public
   */

  assert.isExtensible = function (obj, msg) {
    new Assertion(obj, msg).to.be.extensible;
  };

  /**
   * ### .isNotExtensible(object)
   *
   * Asserts that `object` is _not_ extensible.
   *
   *     var nonExtensibleObject = Object.preventExtensions({});
   *     var sealedObject = Object.seal({});
   *     var frozenObject = Object.freese({});
   *
   *     assert.isNotExtensible(nonExtensibleObject);
   *     assert.isNotExtensible(sealedObject);
   *     assert.isNotExtensible(frozenObject);
   *
   * @name isNotExtensible
   * @alias notExtensible
   * @param {Object} object
   * @param {String} message _optional_
   * @namespace Assert
   * @api public
   */

  assert.isNotExtensible = function (obj, msg) {
    new Assertion(obj, msg).to.not.be.extensible;
  };

  /**
   * ### .isSealed(object)
   *
   * Asserts that `object` is sealed (cannot have new properties added to it
   * and its existing properties cannot be removed).
   *
   *     var sealedObject = Object.seal({});
   *     var frozenObject = Object.seal({});
   *
   *     assert.isSealed(sealedObject);
   *     assert.isSealed(frozenObject);
   *
   * @name isSealed
   * @alias sealed
   * @param {Object} object
   * @param {String} message _optional_
   * @namespace Assert
   * @api public
   */

  assert.isSealed = function (obj, msg) {
    new Assertion(obj, msg).to.be.sealed;
  };

  /**
   * ### .isNotSealed(object)
   *
   * Asserts that `object` is _not_ sealed.
   *
   *     assert.isNotSealed({});
   *
   * @name isNotSealed
   * @alias notSealed
   * @param {Object} object
   * @param {String} message _optional_
   * @namespace Assert
   * @api public
   */

  assert.isNotSealed = function (obj, msg) {
    new Assertion(obj, msg).to.not.be.sealed;
  };

  /**
   * ### .isFrozen(object)
   *
   * Asserts that `object` is frozen (cannot have new properties added to it
   * and its existing properties cannot be modified).
   *
   *     var frozenObject = Object.freeze({});
   *     assert.frozen(frozenObject);
   *
   * @name isFrozen
   * @alias frozen
   * @param {Object} object
   * @param {String} message _optional_
   * @namespace Assert
   * @api public
   */

  assert.isFrozen = function (obj, msg) {
    new Assertion(obj, msg).to.be.frozen;
  };

  /**
   * ### .isNotFrozen(object)
   *
   * Asserts that `object` is _not_ frozen.
   *
   *     assert.isNotFrozen({});
   *
   * @name isNotFrozen
   * @alias notFrozen
   * @param {Object} object
   * @param {String} message _optional_
   * @namespace Assert
   * @api public
   */

  assert.isNotFrozen = function (obj, msg) {
    new Assertion(obj, msg).to.not.be.frozen;
  };

  /*!
   * Aliases.
   */

  (function alias(name, as){
    assert[as] = assert[name];
    return alias;
  })
  ('isOk', 'ok')
  ('isNotOk', 'notOk')
  ('throws', 'throw')
  ('throws', 'Throw')
  ('isExtensible', 'extensible')
  ('isNotExtensible', 'notExtensible')
  ('isSealed', 'sealed')
  ('isNotSealed', 'notSealed')
  ('isFrozen', 'frozen')
  ('isNotFrozen', 'notFrozen');
};

},{}],7:[function(require,module,exports){
/*!
 * chai
 * Copyright(c) 2011-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

module.exports = function (chai, util) {
  chai.expect = function (val, message) {
    return new chai.Assertion(val, message);
  };

  /**
   * ### .fail(actual, expected, [message], [operator])
   *
   * Throw a failure.
   *
   * @name fail
   * @param {Mixed} actual
   * @param {Mixed} expected
   * @param {String} message
   * @param {String} operator
   * @namespace Expect
   * @api public
   */

  chai.expect.fail = function (actual, expected, message, operator) {
    message = message || 'expect.fail()';
    throw new chai.AssertionError(message, {
        actual: actual
      , expected: expected
      , operator: operator
    }, chai.expect.fail);
  };
};

},{}],8:[function(require,module,exports){
/*!
 * chai
 * Copyright(c) 2011-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

module.exports = function (chai, util) {
  var Assertion = chai.Assertion;

  function loadShould () {
    // explicitly define this method as function as to have it's name to include as `ssfi`
    function shouldGetter() {
      if (this instanceof String || this instanceof Number || this instanceof Boolean ) {
        return new Assertion(this.valueOf(), null, shouldGetter);
      }
      return new Assertion(this, null, shouldGetter);
    }
    function shouldSetter(value) {
      // See https://github.com/chaijs/chai/issues/86: this makes
      // `whatever.should = someValue` actually set `someValue`, which is
      // especially useful for `global.should = require('chai').should()`.
      //
      // Note that we have to use [[DefineProperty]] instead of [[Put]]
      // since otherwise we would trigger this very setter!
      Object.defineProperty(this, 'should', {
        value: value,
        enumerable: true,
        configurable: true,
        writable: true
      });
    }
    // modify Object.prototype to have `should`
    Object.defineProperty(Object.prototype, 'should', {
      set: shouldSetter
      , get: shouldGetter
      , configurable: true
    });

    var should = {};

    /**
     * ### .fail(actual, expected, [message], [operator])
     *
     * Throw a failure.
     *
     * @name fail
     * @param {Mixed} actual
     * @param {Mixed} expected
     * @param {String} message
     * @param {String} operator
     * @namespace Should
     * @api public
     */

    should.fail = function (actual, expected, message, operator) {
      message = message || 'should.fail()';
      throw new chai.AssertionError(message, {
          actual: actual
        , expected: expected
        , operator: operator
      }, should.fail);
    };

    /**
     * ### .equal(actual, expected, [message])
     *
     * Asserts non-strict equality (`==`) of `actual` and `expected`.
     *
     *     should.equal(3, '3', '== coerces values to strings');
     *
     * @name equal
     * @param {Mixed} actual
     * @param {Mixed} expected
     * @param {String} message
     * @namespace Should
     * @api public
     */

    should.equal = function (val1, val2, msg) {
      new Assertion(val1, msg).to.equal(val2);
    };

    /**
     * ### .throw(function, [constructor/string/regexp], [string/regexp], [message])
     *
     * Asserts that `function` will throw an error that is an instance of
     * `constructor`, or alternately that it will throw an error with message
     * matching `regexp`.
     *
     *     should.throw(fn, 'function throws a reference error');
     *     should.throw(fn, /function throws a reference error/);
     *     should.throw(fn, ReferenceError);
     *     should.throw(fn, ReferenceError, 'function throws a reference error');
     *     should.throw(fn, ReferenceError, /function throws a reference error/);
     *
     * @name throw
     * @alias Throw
     * @param {Function} function
     * @param {ErrorConstructor} constructor
     * @param {RegExp} regexp
     * @param {String} message
     * @see https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Error#Error_types
     * @namespace Should
     * @api public
     */

    should.Throw = function (fn, errt, errs, msg) {
      new Assertion(fn, msg).to.Throw(errt, errs);
    };

    /**
     * ### .exist
     *
     * Asserts that the target is neither `null` nor `undefined`.
     *
     *     var foo = 'hi';
     *
     *     should.exist(foo, 'foo exists');
     *
     * @name exist
     * @namespace Should
     * @api public
     */

    should.exist = function (val, msg) {
      new Assertion(val, msg).to.exist;
    }

    // negation
    should.not = {}

    /**
     * ### .not.equal(actual, expected, [message])
     *
     * Asserts non-strict inequality (`!=`) of `actual` and `expected`.
     *
     *     should.not.equal(3, 4, 'these numbers are not equal');
     *
     * @name not.equal
     * @param {Mixed} actual
     * @param {Mixed} expected
     * @param {String} message
     * @namespace Should
     * @api public
     */

    should.not.equal = function (val1, val2, msg) {
      new Assertion(val1, msg).to.not.equal(val2);
    };

    /**
     * ### .throw(function, [constructor/regexp], [message])
     *
     * Asserts that `function` will _not_ throw an error that is an instance of
     * `constructor`, or alternately that it will not throw an error with message
     * matching `regexp`.
     *
     *     should.not.throw(fn, Error, 'function does not throw');
     *
     * @name not.throw
     * @alias not.Throw
     * @param {Function} function
     * @param {ErrorConstructor} constructor
     * @param {RegExp} regexp
     * @param {String} message
     * @see https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Error#Error_types
     * @namespace Should
     * @api public
     */

    should.not.Throw = function (fn, errt, errs, msg) {
      new Assertion(fn, msg).to.not.Throw(errt, errs);
    };

    /**
     * ### .not.exist
     *
     * Asserts that the target is neither `null` nor `undefined`.
     *
     *     var bar = null;
     *
     *     should.not.exist(bar, 'bar does not exist');
     *
     * @name not.exist
     * @namespace Should
     * @api public
     */

    should.not.exist = function (val, msg) {
      new Assertion(val, msg).to.not.exist;
    }

    should['throw'] = should['Throw'];
    should.not['throw'] = should.not['Throw'];

    return should;
  };

  chai.should = loadShould;
  chai.Should = loadShould;
};

},{}],9:[function(require,module,exports){
/*!
 * Chai - addChainingMethod utility
 * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

/*!
 * Module dependencies
 */

var transferFlags = require('./transferFlags');
var flag = require('./flag');
var config = require('../config');

/*!
 * Module variables
 */

// Check whether `__proto__` is supported
var hasProtoSupport = '__proto__' in Object;

// Without `__proto__` support, this module will need to add properties to a function.
// However, some Function.prototype methods cannot be overwritten,
// and there seems no easy cross-platform way to detect them (@see chaijs/chai/issues/69).
var excludeNames = /^(?:length|name|arguments|caller)$/;

// Cache `Function` properties
var call  = Function.prototype.call,
    apply = Function.prototype.apply;

/**
 * ### addChainableMethod (ctx, name, method, chainingBehavior)
 *
 * Adds a method to an object, such that the method can also be chained.
 *
 *     utils.addChainableMethod(chai.Assertion.prototype, 'foo', function (str) {
 *       var obj = utils.flag(this, 'object');
 *       new chai.Assertion(obj).to.be.equal(str);
 *     });
 *
 * Can also be accessed directly from `chai.Assertion`.
 *
 *     chai.Assertion.addChainableMethod('foo', fn, chainingBehavior);
 *
 * The result can then be used as both a method assertion, executing both `method` and
 * `chainingBehavior`, or as a language chain, which only executes `chainingBehavior`.
 *
 *     expect(fooStr).to.be.foo('bar');
 *     expect(fooStr).to.be.foo.equal('foo');
 *
 * @param {Object} ctx object to which the method is added
 * @param {String} name of method to add
 * @param {Function} method function to be used for `name`, when called
 * @param {Function} chainingBehavior function to be called every time the property is accessed
 * @namespace Utils
 * @name addChainableMethod
 * @api public
 */

module.exports = function (ctx, name, method, chainingBehavior) {
  if (typeof chainingBehavior !== 'function') {
    chainingBehavior = function () { };
  }

  var chainableBehavior = {
      method: method
    , chainingBehavior: chainingBehavior
  };

  // save the methods so we can overwrite them later, if we need to.
  if (!ctx.__methods) {
    ctx.__methods = {};
  }
  ctx.__methods[name] = chainableBehavior;

  Object.defineProperty(ctx, name,
    { get: function () {
        chainableBehavior.chainingBehavior.call(this);

        var assert = function assert() {
          var old_ssfi = flag(this, 'ssfi');
          if (old_ssfi && config.includeStack === false)
            flag(this, 'ssfi', assert);
          var result = chainableBehavior.method.apply(this, arguments);
          return result === undefined ? this : result;
        };

        // Use `__proto__` if available
        if (hasProtoSupport) {
          // Inherit all properties from the object by replacing the `Function` prototype
          var prototype = assert.__proto__ = Object.create(this);
          // Restore the `call` and `apply` methods from `Function`
          prototype.call = call;
          prototype.apply = apply;
        }
        // Otherwise, redefine all properties (slow!)
        else {
          var asserterNames = Object.getOwnPropertyNames(ctx);
          asserterNames.forEach(function (asserterName) {
            if (!excludeNames.test(asserterName)) {
              var pd = Object.getOwnPropertyDescriptor(ctx, asserterName);
              Object.defineProperty(assert, asserterName, pd);
            }
          });
        }

        transferFlags(this, assert);
        return assert;
      }
    , configurable: true
  });
};

},{"../config":4,"./flag":13,"./transferFlags":29}],10:[function(require,module,exports){
/*!
 * Chai - addMethod utility
 * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

var config = require('../config');

/**
 * ### .addMethod (ctx, name, method)
 *
 * Adds a method to the prototype of an object.
 *
 *     utils.addMethod(chai.Assertion.prototype, 'foo', function (str) {
 *       var obj = utils.flag(this, 'object');
 *       new chai.Assertion(obj).to.be.equal(str);
 *     });
 *
 * Can also be accessed directly from `chai.Assertion`.
 *
 *     chai.Assertion.addMethod('foo', fn);
 *
 * Then can be used as any other assertion.
 *
 *     expect(fooStr).to.be.foo('bar');
 *
 * @param {Object} ctx object to which the method is added
 * @param {String} name of method to add
 * @param {Function} method function to be used for name
 * @namespace Utils
 * @name addMethod
 * @api public
 */
var flag = require('./flag');

module.exports = function (ctx, name, method) {
  ctx[name] = function () {
    var old_ssfi = flag(this, 'ssfi');
    if (old_ssfi && config.includeStack === false)
      flag(this, 'ssfi', ctx[name]);
    var result = method.apply(this, arguments);
    return result === undefined ? this : result;
  };
};

},{"../config":4,"./flag":13}],11:[function(require,module,exports){
/*!
 * Chai - addProperty utility
 * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

var config = require('../config');
var flag = require('./flag');

/**
 * ### addProperty (ctx, name, getter)
 *
 * Adds a property to the prototype of an object.
 *
 *     utils.addProperty(chai.Assertion.prototype, 'foo', function () {
 *       var obj = utils.flag(this, 'object');
 *       new chai.Assertion(obj).to.be.instanceof(Foo);
 *     });
 *
 * Can also be accessed directly from `chai.Assertion`.
 *
 *     chai.Assertion.addProperty('foo', fn);
 *
 * Then can be used as any other assertion.
 *
 *     expect(myFoo).to.be.foo;
 *
 * @param {Object} ctx object to which the property is added
 * @param {String} name of property to add
 * @param {Function} getter function to be used for name
 * @namespace Utils
 * @name addProperty
 * @api public
 */

module.exports = function (ctx, name, getter) {
  Object.defineProperty(ctx, name,
    { get: function addProperty() {
        var old_ssfi = flag(this, 'ssfi');
        if (old_ssfi && config.includeStack === false)
          flag(this, 'ssfi', addProperty);

        var result = getter.call(this);
        return result === undefined ? this : result;
      }
    , configurable: true
  });
};

},{"../config":4,"./flag":13}],12:[function(require,module,exports){
/*!
 * Chai - expectTypes utility
 * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

/**
 * ### expectTypes(obj, types)
 *
 * Ensures that the object being tested against is of a valid type.
 *
 *     utils.expectTypes(this, ['array', 'object', 'string']);
 *
 * @param {Mixed} obj constructed Assertion
 * @param {Array} type A list of allowed types for this assertion
 * @namespace Utils
 * @name expectTypes
 * @api public
 */

var AssertionError = require('assertion-error');
var flag = require('./flag');
var type = require('type-detect');

module.exports = function (obj, types) {
  var obj = flag(obj, 'object');
  types = types.map(function (t) { return t.toLowerCase(); });
  types.sort();

  // Transforms ['lorem', 'ipsum'] into 'a lirum, or an ipsum'
  var str = types.map(function (t, index) {
    var art = ~[ 'a', 'e', 'i', 'o', 'u' ].indexOf(t.charAt(0)) ? 'an' : 'a';
    var or = types.length > 1 && index === types.length - 1 ? 'or ' : '';
    return or + art + ' ' + t;
  }).join(', ');

  if (!types.some(function (expected) { return type(obj) === expected; })) {
    throw new AssertionError(
      'object tested must be ' + str + ', but ' + type(obj) + ' given'
    );
  }
};

},{"./flag":13,"assertion-error":30,"type-detect":35}],13:[function(require,module,exports){
/*!
 * Chai - flag utility
 * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

/**
 * ### flag(object, key, [value])
 *
 * Get or set a flag value on an object. If a
 * value is provided it will be set, else it will
 * return the currently set value or `undefined` if
 * the value is not set.
 *
 *     utils.flag(this, 'foo', 'bar'); // setter
 *     utils.flag(this, 'foo'); // getter, returns `bar`
 *
 * @param {Object} object constructed Assertion
 * @param {String} key
 * @param {Mixed} value (optional)
 * @namespace Utils
 * @name flag
 * @api private
 */

module.exports = function (obj, key, value) {
  var flags = obj.__flags || (obj.__flags = Object.create(null));
  if (arguments.length === 3) {
    flags[key] = value;
  } else {
    return flags[key];
  }
};

},{}],14:[function(require,module,exports){
/*!
 * Chai - getActual utility
 * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

/**
 * # getActual(object, [actual])
 *
 * Returns the `actual` value for an Assertion
 *
 * @param {Object} object (constructed Assertion)
 * @param {Arguments} chai.Assertion.prototype.assert arguments
 * @namespace Utils
 * @name getActual
 */

module.exports = function (obj, args) {
  return args.length > 4 ? args[4] : obj._obj;
};

},{}],15:[function(require,module,exports){
/*!
 * Chai - getEnumerableProperties utility
 * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

/**
 * ### .getEnumerableProperties(object)
 *
 * This allows the retrieval of enumerable property names of an object,
 * inherited or not.
 *
 * @param {Object} object
 * @returns {Array}
 * @namespace Utils
 * @name getEnumerableProperties
 * @api public
 */

module.exports = function getEnumerableProperties(object) {
  var result = [];
  for (var name in object) {
    result.push(name);
  }
  return result;
};

},{}],16:[function(require,module,exports){
/*!
 * Chai - message composition utility
 * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

/*!
 * Module dependancies
 */

var flag = require('./flag')
  , getActual = require('./getActual')
  , inspect = require('./inspect')
  , objDisplay = require('./objDisplay');

/**
 * ### .getMessage(object, message, negateMessage)
 *
 * Construct the error message based on flags
 * and template tags. Template tags will return
 * a stringified inspection of the object referenced.
 *
 * Message template tags:
 * - `#{this}` current asserted object
 * - `#{act}` actual value
 * - `#{exp}` expected value
 *
 * @param {Object} object (constructed Assertion)
 * @param {Arguments} chai.Assertion.prototype.assert arguments
 * @namespace Utils
 * @name getMessage
 * @api public
 */

module.exports = function (obj, args) {
  var negate = flag(obj, 'negate')
    , val = flag(obj, 'object')
    , expected = args[3]
    , actual = getActual(obj, args)
    , msg = negate ? args[2] : args[1]
    , flagMsg = flag(obj, 'message');

  if(typeof msg === "function") msg = msg();
  msg = msg || '';
  msg = msg
    .replace(/#\{this\}/g, function () { return objDisplay(val); })
    .replace(/#\{act\}/g, function () { return objDisplay(actual); })
    .replace(/#\{exp\}/g, function () { return objDisplay(expected); });

  return flagMsg ? flagMsg + ': ' + msg : msg;
};

},{"./flag":13,"./getActual":14,"./inspect":23,"./objDisplay":24}],17:[function(require,module,exports){
/*!
 * Chai - getName utility
 * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

/**
 * # getName(func)
 *
 * Gets the name of a function, in a cross-browser way.
 *
 * @param {Function} a function (usually a constructor)
 * @namespace Utils
 * @name getName
 */

module.exports = function (func) {
  if (func.name) return func.name;

  var match = /^\s?function ([^(]*)\(/.exec(func);
  return match && match[1] ? match[1] : "";
};

},{}],18:[function(require,module,exports){
/*!
 * Chai - getPathInfo utility
 * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

var hasProperty = require('./hasProperty');

/**
 * ### .getPathInfo(path, object)
 *
 * This allows the retrieval of property info in an
 * object given a string path.
 *
 * The path info consists of an object with the
 * following properties:
 *
 * * parent - The parent object of the property referenced by `path`
 * * name - The name of the final property, a number if it was an array indexer
 * * value - The value of the property, if it exists, otherwise `undefined`
 * * exists - Whether the property exists or not
 *
 * @param {String} path
 * @param {Object} object
 * @returns {Object} info
 * @namespace Utils
 * @name getPathInfo
 * @api public
 */

module.exports = function getPathInfo(path, obj) {
  var parsed = parsePath(path),
      last = parsed[parsed.length - 1];

  var info = {
    parent: parsed.length > 1 ? _getPathValue(parsed, obj, parsed.length - 1) : obj,
    name: last.p || last.i,
    value: _getPathValue(parsed, obj)
  };
  info.exists = hasProperty(info.name, info.parent);

  return info;
};


/*!
 * ## parsePath(path)
 *
 * Helper function used to parse string object
 * paths. Use in conjunction with `_getPathValue`.
 *
 *      var parsed = parsePath('myobject.property.subprop');
 *
 * ### Paths:
 *
 * * Can be as near infinitely deep and nested
 * * Arrays are also valid using the formal `myobject.document[3].property`.
 * * Literal dots and brackets (not delimiter) must be backslash-escaped.
 *
 * @param {String} path
 * @returns {Object} parsed
 * @api private
 */

function parsePath (path) {
  var str = path.replace(/([^\\])\[/g, '$1.[')
    , parts = str.match(/(\\\.|[^.]+?)+/g);
  return parts.map(function (value) {
    var re = /^\[(\d+)\]$/
      , mArr = re.exec(value);
    if (mArr) return { i: parseFloat(mArr[1]) };
    else return { p: value.replace(/\\([.\[\]])/g, '$1') };
  });
}


/*!
 * ## _getPathValue(parsed, obj)
 *
 * Helper companion function for `.parsePath` that returns
 * the value located at the parsed address.
 *
 *      var value = getPathValue(parsed, obj);
 *
 * @param {Object} parsed definition from `parsePath`.
 * @param {Object} object to search against
 * @param {Number} object to search against
 * @returns {Object|Undefined} value
 * @api private
 */

function _getPathValue (parsed, obj, index) {
  var tmp = obj
    , res;

  index = (index === undefined ? parsed.length : index);

  for (var i = 0, l = index; i < l; i++) {
    var part = parsed[i];
    if (tmp) {
      if ('undefined' !== typeof part.p)
        tmp = tmp[part.p];
      else if ('undefined' !== typeof part.i)
        tmp = tmp[part.i];
      if (i == (l - 1)) res = tmp;
    } else {
      res = undefined;
    }
  }
  return res;
}

},{"./hasProperty":21}],19:[function(require,module,exports){
/*!
 * Chai - getPathValue utility
 * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
 * @see https://github.com/logicalparadox/filtr
 * MIT Licensed
 */

var getPathInfo = require('./getPathInfo');

/**
 * ### .getPathValue(path, object)
 *
 * This allows the retrieval of values in an
 * object given a string path.
 *
 *     var obj = {
 *         prop1: {
 *             arr: ['a', 'b', 'c']
 *           , str: 'Hello'
 *         }
 *       , prop2: {
 *             arr: [ { nested: 'Universe' } ]
 *           , str: 'Hello again!'
 *         }
 *     }
 *
 * The following would be the results.
 *
 *     getPathValue('prop1.str', obj); // Hello
 *     getPathValue('prop1.att[2]', obj); // b
 *     getPathValue('prop2.arr[0].nested', obj); // Universe
 *
 * @param {String} path
 * @param {Object} object
 * @returns {Object} value or `undefined`
 * @namespace Utils
 * @name getPathValue
 * @api public
 */
module.exports = function(path, obj) {
  var info = getPathInfo(path, obj);
  return info.value;
};

},{"./getPathInfo":18}],20:[function(require,module,exports){
/*!
 * Chai - getProperties utility
 * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

/**
 * ### .getProperties(object)
 *
 * This allows the retrieval of property names of an object, enumerable or not,
 * inherited or not.
 *
 * @param {Object} object
 * @returns {Array}
 * @namespace Utils
 * @name getProperties
 * @api public
 */

module.exports = function getProperties(object) {
  var result = Object.getOwnPropertyNames(object);

  function addProperty(property) {
    if (result.indexOf(property) === -1) {
      result.push(property);
    }
  }

  var proto = Object.getPrototypeOf(object);
  while (proto !== null) {
    Object.getOwnPropertyNames(proto).forEach(addProperty);
    proto = Object.getPrototypeOf(proto);
  }

  return result;
};

},{}],21:[function(require,module,exports){
/*!
 * Chai - hasProperty utility
 * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

var type = require('type-detect');

/**
 * ### .hasProperty(object, name)
 *
 * This allows checking whether an object has
 * named property or numeric array index.
 *
 * Basically does the same thing as the `in`
 * operator but works properly with natives
 * and null/undefined values.
 *
 *     var obj = {
 *         arr: ['a', 'b', 'c']
 *       , str: 'Hello'
 *     }
 *
 * The following would be the results.
 *
 *     hasProperty('str', obj);  // true
 *     hasProperty('constructor', obj);  // true
 *     hasProperty('bar', obj);  // false
 *
 *     hasProperty('length', obj.str); // true
 *     hasProperty(1, obj.str);  // true
 *     hasProperty(5, obj.str);  // false
 *
 *     hasProperty('length', obj.arr);  // true
 *     hasProperty(2, obj.arr);  // true
 *     hasProperty(3, obj.arr);  // false
 *
 * @param {Objuect} object
 * @param {String|Number} name
 * @returns {Boolean} whether it exists
 * @namespace Utils
 * @name getPathInfo
 * @api public
 */

var literals = {
    'number': Number
  , 'string': String
};

module.exports = function hasProperty(name, obj) {
  var ot = type(obj);

  // Bad Object, obviously no props at all
  if(ot === 'null' || ot === 'undefined')
    return false;

  // The `in` operator does not work with certain literals
  // box these before the check
  if(literals[ot] && typeof obj !== 'object')
    obj = new literals[ot](obj);

  return name in obj;
};

},{"type-detect":35}],22:[function(require,module,exports){
/*!
 * chai
 * Copyright(c) 2011 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

/*!
 * Main exports
 */

var exports = module.exports = {};

/*!
 * test utility
 */

exports.test = require('./test');

/*!
 * type utility
 */

exports.type = require('type-detect');

/*!
 * expectTypes utility
 */
exports.expectTypes = require('./expectTypes');

/*!
 * message utility
 */

exports.getMessage = require('./getMessage');

/*!
 * actual utility
 */

exports.getActual = require('./getActual');

/*!
 * Inspect util
 */

exports.inspect = require('./inspect');

/*!
 * Object Display util
 */

exports.objDisplay = require('./objDisplay');

/*!
 * Flag utility
 */

exports.flag = require('./flag');

/*!
 * Flag transferring utility
 */

exports.transferFlags = require('./transferFlags');

/*!
 * Deep equal utility
 */

exports.eql = require('deep-eql');

/*!
 * Deep path value
 */

exports.getPathValue = require('./getPathValue');

/*!
 * Deep path info
 */

exports.getPathInfo = require('./getPathInfo');

/*!
 * Check if a property exists
 */

exports.hasProperty = require('./hasProperty');

/*!
 * Function name
 */

exports.getName = require('./getName');

/*!
 * add Property
 */

exports.addProperty = require('./addProperty');

/*!
 * add Method
 */

exports.addMethod = require('./addMethod');

/*!
 * overwrite Property
 */

exports.overwriteProperty = require('./overwriteProperty');

/*!
 * overwrite Method
 */

exports.overwriteMethod = require('./overwriteMethod');

/*!
 * Add a chainable method
 */

exports.addChainableMethod = require('./addChainableMethod');

/*!
 * Overwrite chainable method
 */

exports.overwriteChainableMethod = require('./overwriteChainableMethod');

},{"./addChainableMethod":9,"./addMethod":10,"./addProperty":11,"./expectTypes":12,"./flag":13,"./getActual":14,"./getMessage":16,"./getName":17,"./getPathInfo":18,"./getPathValue":19,"./hasProperty":21,"./inspect":23,"./objDisplay":24,"./overwriteChainableMethod":25,"./overwriteMethod":26,"./overwriteProperty":27,"./test":28,"./transferFlags":29,"deep-eql":31,"type-detect":35}],23:[function(require,module,exports){
// This is (almost) directly from Node.js utils
// https://github.com/joyent/node/blob/f8c335d0caf47f16d31413f89aa28eda3878e3aa/lib/util.js

var getName = require('./getName');
var getProperties = require('./getProperties');
var getEnumerableProperties = require('./getEnumerableProperties');

module.exports = inspect;

/**
 * Echos the value of a value. Trys to print the value out
 * in the best way possible given the different types.
 *
 * @param {Object} obj The object to print out.
 * @param {Boolean} showHidden Flag that shows hidden (not enumerable)
 *    properties of objects.
 * @param {Number} depth Depth in which to descend in object. Default is 2.
 * @param {Boolean} colors Flag to turn on ANSI escape codes to color the
 *    output. Default is false (no coloring).
 * @namespace Utils
 * @name inspect
 */
function inspect(obj, showHidden, depth, colors) {
  var ctx = {
    showHidden: showHidden,
    seen: [],
    stylize: function (str) { return str; }
  };
  return formatValue(ctx, obj, (typeof depth === 'undefined' ? 2 : depth));
}

// Returns true if object is a DOM element.
var isDOMElement = function (object) {
  if (typeof HTMLElement === 'object') {
    return object instanceof HTMLElement;
  } else {
    return object &&
      typeof object === 'object' &&
      object.nodeType === 1 &&
      typeof object.nodeName === 'string';
  }
};

function formatValue(ctx, value, recurseTimes) {
  // Provide a hook for user-specified inspect functions.
  // Check that value is an object with an inspect function on it
  if (value && typeof value.inspect === 'function' &&
      // Filter out the util module, it's inspect function is special
      value.inspect !== exports.inspect &&
      // Also filter out any prototype objects using the circular check.
      !(value.constructor && value.constructor.prototype === value)) {
    var ret = value.inspect(recurseTimes);
    if (typeof ret !== 'string') {
      ret = formatValue(ctx, ret, recurseTimes);
    }
    return ret;
  }

  // Primitive types cannot have properties
  var primitive = formatPrimitive(ctx, value);
  if (primitive) {
    return primitive;
  }

  // If this is a DOM element, try to get the outer HTML.
  if (isDOMElement(value)) {
    if ('outerHTML' in value) {
      return value.outerHTML;
      // This value does not have an outerHTML attribute,
      //   it could still be an XML element
    } else {
      // Attempt to serialize it
      try {
        if (document.xmlVersion) {
          var xmlSerializer = new XMLSerializer();
          return xmlSerializer.serializeToString(value);
        } else {
          // Firefox 11- do not support outerHTML
          //   It does, however, support innerHTML
          //   Use the following to render the element
          var ns = "http://www.w3.org/1999/xhtml";
          var container = document.createElementNS(ns, '_');

          container.appendChild(value.cloneNode(false));
          html = container.innerHTML
            .replace('><', '>' + value.innerHTML + '<');
          container.innerHTML = '';
          return html;
        }
      } catch (err) {
        // This could be a non-native DOM implementation,
        //   continue with the normal flow:
        //   printing the element as if it is an object.
      }
    }
  }

  // Look up the keys of the object.
  var visibleKeys = getEnumerableProperties(value);
  var keys = ctx.showHidden ? getProperties(value) : visibleKeys;

  // Some type of object without properties can be shortcutted.
  // In IE, errors have a single `stack` property, or if they are vanilla `Error`,
  // a `stack` plus `description` property; ignore those for consistency.
  if (keys.length === 0 || (isError(value) && (
      (keys.length === 1 && keys[0] === 'stack') ||
      (keys.length === 2 && keys[0] === 'description' && keys[1] === 'stack')
     ))) {
    if (typeof value === 'function') {
      var name = getName(value);
      var nameSuffix = name ? ': ' + name : '';
      return ctx.stylize('[Function' + nameSuffix + ']', 'special');
    }
    if (isRegExp(value)) {
      return ctx.stylize(RegExp.prototype.toString.call(value), 'regexp');
    }
    if (isDate(value)) {
      return ctx.stylize(Date.prototype.toUTCString.call(value), 'date');
    }
    if (isError(value)) {
      return formatError(value);
    }
  }

  var base = '', array = false, braces = ['{', '}'];

  // Make Array say that they are Array
  if (isArray(value)) {
    array = true;
    braces = ['[', ']'];
  }

  // Make functions say that they are functions
  if (typeof value === 'function') {
    var name = getName(value);
    var nameSuffix = name ? ': ' + name : '';
    base = ' [Function' + nameSuffix + ']';
  }

  // Make RegExps say that they are RegExps
  if (isRegExp(value)) {
    base = ' ' + RegExp.prototype.toString.call(value);
  }

  // Make dates with properties first say the date
  if (isDate(value)) {
    base = ' ' + Date.prototype.toUTCString.call(value);
  }

  // Make error with message first say the error
  if (isError(value)) {
    return formatError(value);
  }

  if (keys.length === 0 && (!array || value.length == 0)) {
    return braces[0] + base + braces[1];
  }

  if (recurseTimes < 0) {
    if (isRegExp(value)) {
      return ctx.stylize(RegExp.prototype.toString.call(value), 'regexp');
    } else {
      return ctx.stylize('[Object]', 'special');
    }
  }

  ctx.seen.push(value);

  var output;
  if (array) {
    output = formatArray(ctx, value, recurseTimes, visibleKeys, keys);
  } else {
    output = keys.map(function(key) {
      return formatProperty(ctx, value, recurseTimes, visibleKeys, key, array);
    });
  }

  ctx.seen.pop();

  return reduceToSingleString(output, base, braces);
}


function formatPrimitive(ctx, value) {
  switch (typeof value) {
    case 'undefined':
      return ctx.stylize('undefined', 'undefined');

    case 'string':
      var simple = '\'' + JSON.stringify(value).replace(/^"|"$/g, '')
                                               .replace(/'/g, "\\'")
                                               .replace(/\\"/g, '"') + '\'';
      return ctx.stylize(simple, 'string');

    case 'number':
      if (value === 0 && (1/value) === -Infinity) {
        return ctx.stylize('-0', 'number');
      }
      return ctx.stylize('' + value, 'number');

    case 'boolean':
      return ctx.stylize('' + value, 'boolean');
  }
  // For some reason typeof null is "object", so special case here.
  if (value === null) {
    return ctx.stylize('null', 'null');
  }
}


function formatError(value) {
  return '[' + Error.prototype.toString.call(value) + ']';
}


function formatArray(ctx, value, recurseTimes, visibleKeys, keys) {
  var output = [];
  for (var i = 0, l = value.length; i < l; ++i) {
    if (Object.prototype.hasOwnProperty.call(value, String(i))) {
      output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
          String(i), true));
    } else {
      output.push('');
    }
  }
  keys.forEach(function(key) {
    if (!key.match(/^\d+$/)) {
      output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
          key, true));
    }
  });
  return output;
}


function formatProperty(ctx, value, recurseTimes, visibleKeys, key, array) {
  var name, str;
  if (value.__lookupGetter__) {
    if (value.__lookupGetter__(key)) {
      if (value.__lookupSetter__(key)) {
        str = ctx.stylize('[Getter/Setter]', 'special');
      } else {
        str = ctx.stylize('[Getter]', 'special');
      }
    } else {
      if (value.__lookupSetter__(key)) {
        str = ctx.stylize('[Setter]', 'special');
      }
    }
  }
  if (visibleKeys.indexOf(key) < 0) {
    name = '[' + key + ']';
  }
  if (!str) {
    if (ctx.seen.indexOf(value[key]) < 0) {
      if (recurseTimes === null) {
        str = formatValue(ctx, value[key], null);
      } else {
        str = formatValue(ctx, value[key], recurseTimes - 1);
      }
      if (str.indexOf('\n') > -1) {
        if (array) {
          str = str.split('\n').map(function(line) {
            return '  ' + line;
          }).join('\n').substr(2);
        } else {
          str = '\n' + str.split('\n').map(function(line) {
            return '   ' + line;
          }).join('\n');
        }
      }
    } else {
      str = ctx.stylize('[Circular]', 'special');
    }
  }
  if (typeof name === 'undefined') {
    if (array && key.match(/^\d+$/)) {
      return str;
    }
    name = JSON.stringify('' + key);
    if (name.match(/^"([a-zA-Z_][a-zA-Z_0-9]*)"$/)) {
      name = name.substr(1, name.length - 2);
      name = ctx.stylize(name, 'name');
    } else {
      name = name.replace(/'/g, "\\'")
                 .replace(/\\"/g, '"')
                 .replace(/(^"|"$)/g, "'");
      name = ctx.stylize(name, 'string');
    }
  }

  return name + ': ' + str;
}


function reduceToSingleString(output, base, braces) {
  var numLinesEst = 0;
  var length = output.reduce(function(prev, cur) {
    numLinesEst++;
    if (cur.indexOf('\n') >= 0) numLinesEst++;
    return prev + cur.length + 1;
  }, 0);

  if (length > 60) {
    return braces[0] +
           (base === '' ? '' : base + '\n ') +
           ' ' +
           output.join(',\n  ') +
           ' ' +
           braces[1];
  }

  return braces[0] + base + ' ' + output.join(', ') + ' ' + braces[1];
}

function isArray(ar) {
  return Array.isArray(ar) ||
         (typeof ar === 'object' && objectToString(ar) === '[object Array]');
}

function isRegExp(re) {
  return typeof re === 'object' && objectToString(re) === '[object RegExp]';
}

function isDate(d) {
  return typeof d === 'object' && objectToString(d) === '[object Date]';
}

function isError(e) {
  return typeof e === 'object' && objectToString(e) === '[object Error]';
}

function objectToString(o) {
  return Object.prototype.toString.call(o);
}

},{"./getEnumerableProperties":15,"./getName":17,"./getProperties":20}],24:[function(require,module,exports){
/*!
 * Chai - flag utility
 * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

/*!
 * Module dependancies
 */

var inspect = require('./inspect');
var config = require('../config');

/**
 * ### .objDisplay (object)
 *
 * Determines if an object or an array matches
 * criteria to be inspected in-line for error
 * messages or should be truncated.
 *
 * @param {Mixed} javascript object to inspect
 * @name objDisplay
 * @namespace Utils
 * @api public
 */

module.exports = function (obj) {
  var str = inspect(obj)
    , type = Object.prototype.toString.call(obj);

  if (config.truncateThreshold && str.length >= config.truncateThreshold) {
    if (type === '[object Function]') {
      return !obj.name || obj.name === ''
        ? '[Function]'
        : '[Function: ' + obj.name + ']';
    } else if (type === '[object Array]') {
      return '[ Array(' + obj.length + ') ]';
    } else if (type === '[object Object]') {
      var keys = Object.keys(obj)
        , kstr = keys.length > 2
          ? keys.splice(0, 2).join(', ') + ', ...'
          : keys.join(', ');
      return '{ Object (' + kstr + ') }';
    } else {
      return str;
    }
  } else {
    return str;
  }
};

},{"../config":4,"./inspect":23}],25:[function(require,module,exports){
/*!
 * Chai - overwriteChainableMethod utility
 * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

/**
 * ### overwriteChainableMethod (ctx, name, method, chainingBehavior)
 *
 * Overwites an already existing chainable method
 * and provides access to the previous function or
 * property.  Must return functions to be used for
 * name.
 *
 *     utils.overwriteChainableMethod(chai.Assertion.prototype, 'length',
 *       function (_super) {
 *       }
 *     , function (_super) {
 *       }
 *     );
 *
 * Can also be accessed directly from `chai.Assertion`.
 *
 *     chai.Assertion.overwriteChainableMethod('foo', fn, fn);
 *
 * Then can be used as any other assertion.
 *
 *     expect(myFoo).to.have.length(3);
 *     expect(myFoo).to.have.length.above(3);
 *
 * @param {Object} ctx object whose method / property is to be overwritten
 * @param {String} name of method / property to overwrite
 * @param {Function} method function that returns a function to be used for name
 * @param {Function} chainingBehavior function that returns a function to be used for property
 * @namespace Utils
 * @name overwriteChainableMethod
 * @api public
 */

module.exports = function (ctx, name, method, chainingBehavior) {
  var chainableBehavior = ctx.__methods[name];

  var _chainingBehavior = chainableBehavior.chainingBehavior;
  chainableBehavior.chainingBehavior = function () {
    var result = chainingBehavior(_chainingBehavior).call(this);
    return result === undefined ? this : result;
  };

  var _method = chainableBehavior.method;
  chainableBehavior.method = function () {
    var result = method(_method).apply(this, arguments);
    return result === undefined ? this : result;
  };
};

},{}],26:[function(require,module,exports){
/*!
 * Chai - overwriteMethod utility
 * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

/**
 * ### overwriteMethod (ctx, name, fn)
 *
 * Overwites an already existing method and provides
 * access to previous function. Must return function
 * to be used for name.
 *
 *     utils.overwriteMethod(chai.Assertion.prototype, 'equal', function (_super) {
 *       return function (str) {
 *         var obj = utils.flag(this, 'object');
 *         if (obj instanceof Foo) {
 *           new chai.Assertion(obj.value).to.equal(str);
 *         } else {
 *           _super.apply(this, arguments);
 *         }
 *       }
 *     });
 *
 * Can also be accessed directly from `chai.Assertion`.
 *
 *     chai.Assertion.overwriteMethod('foo', fn);
 *
 * Then can be used as any other assertion.
 *
 *     expect(myFoo).to.equal('bar');
 *
 * @param {Object} ctx object whose method is to be overwritten
 * @param {String} name of method to overwrite
 * @param {Function} method function that returns a function to be used for name
 * @namespace Utils
 * @name overwriteMethod
 * @api public
 */

module.exports = function (ctx, name, method) {
  var _method = ctx[name]
    , _super = function () { return this; };

  if (_method && 'function' === typeof _method)
    _super = _method;

  ctx[name] = function () {
    var result = method(_super).apply(this, arguments);
    return result === undefined ? this : result;
  }
};

},{}],27:[function(require,module,exports){
/*!
 * Chai - overwriteProperty utility
 * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

/**
 * ### overwriteProperty (ctx, name, fn)
 *
 * Overwites an already existing property getter and provides
 * access to previous value. Must return function to use as getter.
 *
 *     utils.overwriteProperty(chai.Assertion.prototype, 'ok', function (_super) {
 *       return function () {
 *         var obj = utils.flag(this, 'object');
 *         if (obj instanceof Foo) {
 *           new chai.Assertion(obj.name).to.equal('bar');
 *         } else {
 *           _super.call(this);
 *         }
 *       }
 *     });
 *
 *
 * Can also be accessed directly from `chai.Assertion`.
 *
 *     chai.Assertion.overwriteProperty('foo', fn);
 *
 * Then can be used as any other assertion.
 *
 *     expect(myFoo).to.be.ok;
 *
 * @param {Object} ctx object whose property is to be overwritten
 * @param {String} name of property to overwrite
 * @param {Function} getter function that returns a getter function to be used for name
 * @namespace Utils
 * @name overwriteProperty
 * @api public
 */

module.exports = function (ctx, name, getter) {
  var _get = Object.getOwnPropertyDescriptor(ctx, name)
    , _super = function () {};

  if (_get && 'function' === typeof _get.get)
    _super = _get.get

  Object.defineProperty(ctx, name,
    { get: function () {
        var result = getter(_super).call(this);
        return result === undefined ? this : result;
      }
    , configurable: true
  });
};

},{}],28:[function(require,module,exports){
/*!
 * Chai - test utility
 * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

/*!
 * Module dependancies
 */

var flag = require('./flag');

/**
 * # test(object, expression)
 *
 * Test and object for expression.
 *
 * @param {Object} object (constructed Assertion)
 * @param {Arguments} chai.Assertion.prototype.assert arguments
 * @namespace Utils
 * @name test
 */

module.exports = function (obj, args) {
  var negate = flag(obj, 'negate')
    , expr = args[0];
  return negate ? !expr : expr;
};

},{"./flag":13}],29:[function(require,module,exports){
/*!
 * Chai - transferFlags utility
 * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

/**
 * ### transferFlags(assertion, object, includeAll = true)
 *
 * Transfer all the flags for `assertion` to `object`. If
 * `includeAll` is set to `false`, then the base Chai
 * assertion flags (namely `object`, `ssfi`, and `message`)
 * will not be transferred.
 *
 *
 *     var newAssertion = new Assertion();
 *     utils.transferFlags(assertion, newAssertion);
 *
 *     var anotherAsseriton = new Assertion(myObj);
 *     utils.transferFlags(assertion, anotherAssertion, false);
 *
 * @param {Assertion} assertion the assertion to transfer the flags from
 * @param {Object} object the object to transfer the flags to; usually a new assertion
 * @param {Boolean} includeAll
 * @namespace Utils
 * @name transferFlags
 * @api private
 */

module.exports = function (assertion, object, includeAll) {
  var flags = assertion.__flags || (assertion.__flags = Object.create(null));

  if (!object.__flags) {
    object.__flags = Object.create(null);
  }

  includeAll = arguments.length === 3 ? includeAll : true;

  for (var flag in flags) {
    if (includeAll ||
        (flag !== 'object' && flag !== 'ssfi' && flag != 'message')) {
      object.__flags[flag] = flags[flag];
    }
  }
};

},{}],30:[function(require,module,exports){
/*!
 * assertion-error
 * Copyright(c) 2013 Jake Luer <jake@qualiancy.com>
 * MIT Licensed
 */

/*!
 * Return a function that will copy properties from
 * one object to another excluding any originally
 * listed. Returned function will create a new `{}`.
 *
 * @param {String} excluded properties ...
 * @return {Function}
 */

function exclude () {
  var excludes = [].slice.call(arguments);

  function excludeProps (res, obj) {
    Object.keys(obj).forEach(function (key) {
      if (!~excludes.indexOf(key)) res[key] = obj[key];
    });
  }

  return function extendExclude () {
    var args = [].slice.call(arguments)
      , i = 0
      , res = {};

    for (; i < args.length; i++) {
      excludeProps(res, args[i]);
    }

    return res;
  };
};

/*!
 * Primary Exports
 */

module.exports = AssertionError;

/**
 * ### AssertionError
 *
 * An extension of the JavaScript `Error` constructor for
 * assertion and validation scenarios.
 *
 * @param {String} message
 * @param {Object} properties to include (optional)
 * @param {callee} start stack function (optional)
 */

function AssertionError (message, _props, ssf) {
  var extend = exclude('name', 'message', 'stack', 'constructor', 'toJSON')
    , props = extend(_props || {});

  // default values
  this.message = message || 'Unspecified AssertionError';
  this.showDiff = false;

  // copy from properties
  for (var key in props) {
    this[key] = props[key];
  }

  // capture stack trace
  ssf = ssf || arguments.callee;
  if (ssf && Error.captureStackTrace) {
    Error.captureStackTrace(this, ssf);
  } else {
    this.stack = new Error().stack;
  }
}

/*!
 * Inherit from Error.prototype
 */

AssertionError.prototype = Object.create(Error.prototype);

/*!
 * Statically set name
 */

AssertionError.prototype.name = 'AssertionError';

/*!
 * Ensure correct constructor
 */

AssertionError.prototype.constructor = AssertionError;

/**
 * Allow errors to be converted to JSON for static transfer.
 *
 * @param {Boolean} include stack (default: `true`)
 * @return {Object} object that can be `JSON.stringify`
 */

AssertionError.prototype.toJSON = function (stack) {
  var extend = exclude('constructor', 'toJSON', 'stack')
    , props = extend({ name: this.name }, this);

  // include stack if exists and not turned off
  if (false !== stack && this.stack) {
    props.stack = this.stack;
  }

  return props;
};

},{}],31:[function(require,module,exports){
module.exports = require('./lib/eql');

},{"./lib/eql":32}],32:[function(require,module,exports){
/*!
 * deep-eql
 * Copyright(c) 2013 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

/*!
 * Module dependencies
 */

var type = require('type-detect');

/*!
 * Buffer.isBuffer browser shim
 */

var Buffer;
try { Buffer = require('buffer').Buffer; }
catch(ex) {
  Buffer = {};
  Buffer.isBuffer = function() { return false; }
}

/*!
 * Primary Export
 */

module.exports = deepEqual;

/**
 * Assert super-strict (egal) equality between
 * two objects of any type.
 *
 * @param {Mixed} a
 * @param {Mixed} b
 * @param {Array} memoised (optional)
 * @return {Boolean} equal match
 */

function deepEqual(a, b, m) {
  if (sameValue(a, b)) {
    return true;
  } else if ('date' === type(a)) {
    return dateEqual(a, b);
  } else if ('regexp' === type(a)) {
    return regexpEqual(a, b);
  } else if (Buffer.isBuffer(a)) {
    return bufferEqual(a, b);
  } else if ('arguments' === type(a)) {
    return argumentsEqual(a, b, m);
  } else if (!typeEqual(a, b)) {
    return false;
  } else if (('object' !== type(a) && 'object' !== type(b))
  && ('array' !== type(a) && 'array' !== type(b))) {
    return sameValue(a, b);
  } else {
    return objectEqual(a, b, m);
  }
}

/*!
 * Strict (egal) equality test. Ensures that NaN always
 * equals NaN and `-0` does not equal `+0`.
 *
 * @param {Mixed} a
 * @param {Mixed} b
 * @return {Boolean} equal match
 */

function sameValue(a, b) {
  if (a === b) return a !== 0 || 1 / a === 1 / b;
  return a !== a && b !== b;
}

/*!
 * Compare the types of two given objects and
 * return if they are equal. Note that an Array
 * has a type of `array` (not `object`) and arguments
 * have a type of `arguments` (not `array`/`object`).
 *
 * @param {Mixed} a
 * @param {Mixed} b
 * @return {Boolean} result
 */

function typeEqual(a, b) {
  return type(a) === type(b);
}

/*!
 * Compare two Date objects by asserting that
 * the time values are equal using `saveValue`.
 *
 * @param {Date} a
 * @param {Date} b
 * @return {Boolean} result
 */

function dateEqual(a, b) {
  if ('date' !== type(b)) return false;
  return sameValue(a.getTime(), b.getTime());
}

/*!
 * Compare two regular expressions by converting them
 * to string and checking for `sameValue`.
 *
 * @param {RegExp} a
 * @param {RegExp} b
 * @return {Boolean} result
 */

function regexpEqual(a, b) {
  if ('regexp' !== type(b)) return false;
  return sameValue(a.toString(), b.toString());
}

/*!
 * Assert deep equality of two `arguments` objects.
 * Unfortunately, these must be sliced to arrays
 * prior to test to ensure no bad behavior.
 *
 * @param {Arguments} a
 * @param {Arguments} b
 * @param {Array} memoize (optional)
 * @return {Boolean} result
 */

function argumentsEqual(a, b, m) {
  if ('arguments' !== type(b)) return false;
  a = [].slice.call(a);
  b = [].slice.call(b);
  return deepEqual(a, b, m);
}

/*!
 * Get enumerable properties of a given object.
 *
 * @param {Object} a
 * @return {Array} property names
 */

function enumerable(a) {
  var res = [];
  for (var key in a) res.push(key);
  return res;
}

/*!
 * Simple equality for flat iterable objects
 * such as Arrays or Node.js buffers.
 *
 * @param {Iterable} a
 * @param {Iterable} b
 * @return {Boolean} result
 */

function iterableEqual(a, b) {
  if (a.length !==  b.length) return false;

  var i = 0;
  var match = true;

  for (; i < a.length; i++) {
    if (a[i] !== b[i]) {
      match = false;
      break;
    }
  }

  return match;
}

/*!
 * Extension to `iterableEqual` specifically
 * for Node.js Buffers.
 *
 * @param {Buffer} a
 * @param {Mixed} b
 * @return {Boolean} result
 */

function bufferEqual(a, b) {
  if (!Buffer.isBuffer(b)) return false;
  return iterableEqual(a, b);
}

/*!
 * Block for `objectEqual` ensuring non-existing
 * values don't get in.
 *
 * @param {Mixed} object
 * @return {Boolean} result
 */

function isValue(a) {
  return a !== null && a !== undefined;
}

/*!
 * Recursively check the equality of two objects.
 * Once basic sameness has been established it will
 * defer to `deepEqual` for each enumerable key
 * in the object.
 *
 * @param {Mixed} a
 * @param {Mixed} b
 * @return {Boolean} result
 */

function objectEqual(a, b, m) {
  if (!isValue(a) || !isValue(b)) {
    return false;
  }

  if (a.prototype !== b.prototype) {
    return false;
  }

  var i;
  if (m) {
    for (i = 0; i < m.length; i++) {
      if ((m[i][0] === a && m[i][1] === b)
      ||  (m[i][0] === b && m[i][1] === a)) {
        return true;
      }
    }
  } else {
    m = [];
  }

  try {
    var ka = enumerable(a);
    var kb = enumerable(b);
  } catch (ex) {
    return false;
  }

  ka.sort();
  kb.sort();

  if (!iterableEqual(ka, kb)) {
    return false;
  }

  m.push([ a, b ]);

  var key;
  for (i = ka.length - 1; i >= 0; i--) {
    key = ka[i];
    if (!deepEqual(a[key], b[key], m)) {
      return false;
    }
  }

  return true;
}

},{"buffer":undefined,"type-detect":33}],33:[function(require,module,exports){
module.exports = require('./lib/type');

},{"./lib/type":34}],34:[function(require,module,exports){
/*!
 * type-detect
 * Copyright(c) 2013 jake luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

/*!
 * Primary Exports
 */

var exports = module.exports = getType;

/*!
 * Detectable javascript natives
 */

var natives = {
    '[object Array]': 'array'
  , '[object RegExp]': 'regexp'
  , '[object Function]': 'function'
  , '[object Arguments]': 'arguments'
  , '[object Date]': 'date'
};

/**
 * ### typeOf (obj)
 *
 * Use several different techniques to determine
 * the type of object being tested.
 *
 *
 * @param {Mixed} object
 * @return {String} object type
 * @api public
 */

function getType (obj) {
  var str = Object.prototype.toString.call(obj);
  if (natives[str]) return natives[str];
  if (obj === null) return 'null';
  if (obj === undefined) return 'undefined';
  if (obj === Object(obj)) return 'object';
  return typeof obj;
}

exports.Library = Library;

/**
 * ### Library
 *
 * Create a repository for custom type detection.
 *
 * ```js
 * var lib = new type.Library;
 * ```
 *
 */

function Library () {
  this.tests = {};
}

/**
 * #### .of (obj)
 *
 * Expose replacement `typeof` detection to the library.
 *
 * ```js
 * if ('string' === lib.of('hello world')) {
 *   // ...
 * }
 * ```
 *
 * @param {Mixed} object to test
 * @return {String} type
 */

Library.prototype.of = getType;

/**
 * #### .define (type, test)
 *
 * Add a test to for the `.test()` assertion.
 *
 * Can be defined as a regular expression:
 *
 * ```js
 * lib.define('int', /^[0-9]+$/);
 * ```
 *
 * ... or as a function:
 *
 * ```js
 * lib.define('bln', function (obj) {
 *   if ('boolean' === lib.of(obj)) return true;
 *   var blns = [ 'yes', 'no', 'true', 'false', 1, 0 ];
 *   if ('string' === lib.of(obj)) obj = obj.toLowerCase();
 *   return !! ~blns.indexOf(obj);
 * });
 * ```
 *
 * @param {String} type
 * @param {RegExp|Function} test
 * @api public
 */

Library.prototype.define = function (type, test) {
  if (arguments.length === 1) return this.tests[type];
  this.tests[type] = test;
  return this;
};

/**
 * #### .test (obj, test)
 *
 * Assert that an object is of type. Will first
 * check natives, and if that does not pass it will
 * use the user defined custom tests.
 *
 * ```js
 * assert(lib.test('1', 'int'));
 * assert(lib.test('yes', 'bln'));
 * ```
 *
 * @param {Mixed} object
 * @param {String} type
 * @return {Boolean} result
 * @api public
 */

Library.prototype.test = function (obj, type) {
  if (type === getType(obj)) return true;
  var test = this.tests[type];

  if (test && 'regexp' === getType(test)) {
    return test.test(obj);
  } else if (test && 'function' === getType(test)) {
    return test(obj);
  } else {
    throw new ReferenceError('Type test "' + type + '" not defined or invalid.');
  }
};

},{}],35:[function(require,module,exports){
arguments[4][33][0].apply(exports,arguments)
},{"./lib/type":36,"dup":33}],36:[function(require,module,exports){
/*!
 * type-detect
 * Copyright(c) 2013 jake luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

/*!
 * Primary Exports
 */

var exports = module.exports = getType;

/**
 * ### typeOf (obj)
 *
 * Use several different techniques to determine
 * the type of object being tested.
 *
 *
 * @param {Mixed} object
 * @return {String} object type
 * @api public
 */
var objectTypeRegexp = /^\[object (.*)\]$/;

function getType(obj) {
  var type = Object.prototype.toString.call(obj).match(objectTypeRegexp)[1].toLowerCase();
  // Let "new String('')" return 'object'
  if (typeof Promise === 'function' && obj instanceof Promise) return 'promise';
  // PhantomJS has type "DOMWindow" for null
  if (obj === null) return 'null';
  // PhantomJS has type "DOMWindow" for undefined
  if (obj === undefined) return 'undefined';
  return type;
}

exports.Library = Library;

/**
 * ### Library
 *
 * Create a repository for custom type detection.
 *
 * ```js
 * var lib = new type.Library;
 * ```
 *
 */

function Library() {
  if (!(this instanceof Library)) return new Library();
  this.tests = {};
}

/**
 * #### .of (obj)
 *
 * Expose replacement `typeof` detection to the library.
 *
 * ```js
 * if ('string' === lib.of('hello world')) {
 *   // ...
 * }
 * ```
 *
 * @param {Mixed} object to test
 * @return {String} type
 */

Library.prototype.of = getType;

/**
 * #### .define (type, test)
 *
 * Add a test to for the `.test()` assertion.
 *
 * Can be defined as a regular expression:
 *
 * ```js
 * lib.define('int', /^[0-9]+$/);
 * ```
 *
 * ... or as a function:
 *
 * ```js
 * lib.define('bln', function (obj) {
 *   if ('boolean' === lib.of(obj)) return true;
 *   var blns = [ 'yes', 'no', 'true', 'false', 1, 0 ];
 *   if ('string' === lib.of(obj)) obj = obj.toLowerCase();
 *   return !! ~blns.indexOf(obj);
 * });
 * ```
 *
 * @param {String} type
 * @param {RegExp|Function} test
 * @api public
 */

Library.prototype.define = function(type, test) {
  if (arguments.length === 1) return this.tests[type];
  this.tests[type] = test;
  return this;
};

/**
 * #### .test (obj, test)
 *
 * Assert that an object is of type. Will first
 * check natives, and if that does not pass it will
 * use the user defined custom tests.
 *
 * ```js
 * assert(lib.test('1', 'int'));
 * assert(lib.test('yes', 'bln'));
 * ```
 *
 * @param {Mixed} object
 * @param {String} type
 * @return {Boolean} result
 * @api public
 */

Library.prototype.test = function(obj, type) {
  if (type === getType(obj)) return true;
  var test = this.tests[type];

  if (test && 'regexp' === getType(test)) {
    return test.test(obj);
  } else if (test && 'function' === getType(test)) {
    return test(obj);
  } else {
    throw new ReferenceError('Type test "' + type + '" not defined or invalid.');
  }
};

},{}]},{},[1])(1)
});