Initial mocha tests

package.json

@@ -20,12 +20,19 @@
   },
   "license": "MIT",
   "engines": {
-    "node": ">=0.10"
+    "node": ">=4.0"
   },
   "devDependencies": {
+    "chai": "^4.1.2",
+    "chai-as-promised": "^7.1.1",
     "grunt": "^0.4.5",
     "grunt-cafe-mocha": "^0.1.13",
     "grunt-contrib-jshint": "^1.1.0",
-    "grunt-groc": "^0.7.1"
+    "grunt-groc": "^0.7.1",
+    "mocha": "^5.1.1",
+    "mock-spawn": "^0.2.6"
+  },
+  "scripts": {
+    "test": "mocha"
   }
 }

src/main.js

@@ -24,20 +24,29 @@ util.inherits(Engine, events.EventEmitter);
 Engine.prototype.runProcess = function () {
     var self = this;
     var deferred = Q.defer();
-    this.engineProcess = spawn(this.engineFile);
+    var numberOfTriesBeforeTimeout = 10;
+    var currentIntervalNumber = 0
     var timer;
+
+    this.engineProcess = spawn(this.engineFile);
+
     this.engineProcess.once('error', function (error) {
         clearInterval(timer);
         deferred.reject(error);
     });
 
     timer = setInterval(function () {
+        currentIntervalNumber += 1;
+
         if (utilities.isProcessRunning(self.engineProcess)) {
             clearInterval(timer);
             deferred.resolve();
+        } else if (currentIntervalNumber === numberOfTriesBeforeTimeout) {
+            clearInterval(timer);
+            deferred.reject(new Error('timeout while starting process'));
         }
-
     }, 100);
+
     return deferred.promise;
 };
 
@@ -189,7 +198,7 @@ Engine.prototype.timeLimitedGoCommand = function (infoHandler,
     var self = this;
     var deferred = Q.defer();
     var pendingData = "";
-    
+
     var engineStdoutListener = function (data) {
         var lines = utilities.getLines(pendingData+data);
         pendingData = lines.incompleteLine ? lines.incompleteLine : "";
@@ -231,7 +240,7 @@ Engine.prototype.timeLimitedGoCommand = function (infoHandler,
 //called for each info line output by the engine.
 Engine.prototype.goCommand = function (commands, infoHandler) {
     var pendingData = "";
-    
+
     var engineStdoutListener = function (data) {
         var lines = utilities.getLines(pendingData+data);
         pendingData = lines.incompleteLine ? lines.incompleteLine : "";
@@ -280,7 +289,7 @@ Engine.prototype.goCommand = function (commands, infoHandler) {
 //called for each info line output by the engine.
 Engine.prototype.goInfiniteCommand = function (infoHandler) {
     var pendingData = "";
-    
+
     var engineStdoutListener = function (data) {
         var lines = utilities.getLines(pendingData+data);
         pendingData = lines.incompleteLine ? lines.incompleteLine : "";
@@ -308,7 +317,7 @@ Engine.prototype.stopCommand = function () {
     var self = this;
     var deferred = Q.defer();
     var pendingData = "";
-    
+
     var engineStdoutListener = function (data) {
         var lines = utilities.getLines(pendingData+data);
         pendingData = lines.incompleteLine ? lines.incompleteLine : "";

test/engine-init.js

@@ -0,0 +1,106 @@
+/**
+ * Setup testing with `chai`.
+ */
+
+var chai = require('chai');
+var chaiAsPromised = require('chai-as-promised');
+chai.use(chaiAsPromised);
+chai.should();
+var expect = chai.expect;
+
+
+
+/**
+ * Setup `child_process.spawn` mocks.
+ */
+var mockSpawn = require('mock-spawn');
+var mySpawn = mockSpawn();
+require('child_process').spawn = mySpawn;
+
+// First spawn -> emit error, exit with status (1).
+mySpawn.sequence.add(function (cb) {
+    this.emit('error', new Error('spawn ' + badEnginePath + ' ENOENT'));
+    setTimeout(function() { return cb(1); }, 10);
+});
+// Second spawn -> slow start of application. Simulate timeout error.
+mySpawn.sequence.add(function (cb) {
+    var self = this;
+
+    setTimeout(function () {
+        self.stdout.write('some output data');
+
+        return cb(0);
+    }, 1500);
+});
+// Third spawn -> normal application start.
+mySpawn.sequence.add(function (cb) {
+    var self = this;
+
+    setTimeout(function () {
+        self.stdout.write('some output data');
+
+        return cb(0);
+    }, 100);
+});
+
+
+
+/**
+ * Some predefined constants to be used in tests.
+ */
+
+var badEnginePath = 'non_existent_engine';
+var testEcecutableFile = 'test_executable';
+
+
+
+/**
+ * Our subject-under-test.
+ */
+
+var Engine = require('../src/main');
+
+
+
+/**
+ * Now the tests start :)
+ */
+
+describe('Engine', function () {
+    describe('contructor', function () {
+        it('throws when no engine path is provided', function () {
+            return expect(function () {
+                new Engine();
+            }).to.throw('Path must be a string. Received undefined')
+        });
+
+        it('does not throw on bad engine path', function () {
+            return expect(function () {
+                new Engine('non_existent_engine');
+            }).to.not.throw()
+        });
+    });
+
+    describe('runProcess', function () {
+        it('throws when tries to launch non existent path', function () {
+            var engine = new Engine(badEnginePath);
+            var promise = engine.runProcess();
+
+            return promise.should.be.rejectedWith('spawn ' + badEnginePath + ' ENOENT');
+        });
+
+        it('throws timeout error if executable does not start within allowed timeout period', function () {
+            var engine = new Engine(testEcecutableFile);
+            var promise = engine.runProcess();
+
+            return promise.should.be.rejectedWith('timeout while starting process');
+        });
+
+        it('does not throw if executable launched OK', function () {
+            var engine = new Engine(testEcecutableFile);
+            var promise = engine.runProcess();
+
+            return promise.should.not.be.rejected;
+        });
+    });
+});