ltest

A Unit, Integration, and System Tests Framework for LFE

Table of Contents

• Introduction
• EUnit Compatibility
• Features
• Using ltest
  • Adding ltest to Your Project
  • Structuring Your Tests
  • Naming Rules
  • Creating Unit Tests
  • Running Your Tests
  • The LFE Test Runner
• Dogfood

Introduction ↟

The original implementation of ltest (as lfeunit) was made due to some difficulties in parsing the Erlang include file for EUnit, eunit.hrl, by LFE (it didn't convert all the Erlang macros). Good news: that has since been fixed!

However, during lfeunit's early existence, additional features were added -- things that EUnit didn't have or were clumsy to use. Such features, improved in ltest, make the creation of not only unit tests, but system and integration tests, easier and more consistent. These are briefly outlined in the next section.

Of particular interest to those coming from the Clojure community, the macros in this library are inspired by Clojure's excellent unit test framework.

Finally, features have been introduced into ltest that have no counterpart in EUnit (e.g., defining tests to be skipped, using behaviours to "tag" types of tests, and a REALLY BEAUTIFUL test runner, etc.)

EUnit Compatibility ↟

The tests created with ltest are compatible with EUnit ane can be run from either Erlang or LFE, using the standard EUnit listener or the ltest listener (test runner).

Features ↟

• (deftest ...) for standard unit tests
• (deftestgen ...) for writing tests with generators, including the standard EUnit test fixtures (see naming caveat below)
• (deftestskip ...) for skipping unit tests
• (list ...)-wrapped tests (of arbitrary depth) for use as test sets
• (tuple ...)-wrapped tests for naming/describing tests (first element of tuple)
• (behaviour ltest-unit) - annotating a test module to be run as a unit test
• (behaviour ltest-integration) - annotating a test module to be run as an integration test
• (behaviour ltest-system) - annotating a test module to be run as a system test
• A custom test runner that over-rides EUnit behaviour and aesthetics

Using ltest ↟

Adding ltest to Your Project ↟

In order to use ltest in your project, all you need to do is add a rebar dep. In your rebar.config file, simply add an extra line for ltest:

{deps, [
    {lfe, ".*", {git, "git://github.com/rvirding/lfe.git", "master"}},
    {ltest, ".*", {git, "git://github.com/lfex/ltest.git", "master"}}
  ]}.

Once you write some tests (see below for how to do that), you can then do this:

$ lfetool tests build
$ lfetool tests unit

Structuring Your Tests ↟

ltest doesn not support putting your unit tests directly in your modules. If you do this, things may break or not work properly, even though Erlang's EUnit does support it.

Instead, you should create a top-level directory in your project called test. In test, create a test cases module for every module your project has, e.g., test/myproj-base-tests.lfe and test/myproj-util-tests.lfe. Obviously, if it makes sense to break things up in a more fine-grained manner, feel free to do so :-)

Furthermore, ltest supports separating unit, integration, and system tests. This is done using custom OTP behaviours. For each test cases module you have created in ./test, be sure to set the behaviour in the (defmodule ...) form. For instance:

  (defmodule my-unit-tests
    (behaviour ltest-unit)
    (export ...))

And two more as well:

  (defmodule my-integration-tests
    (behaviour ltest-integration)
    (export ...))

or

  (defmodule my-system-tests
    (behaviour ltest-system)
    (export ...))

For a working example of such a structure, see the layout of the ltest project itself: it uses just such a setup.

To read more about the distinction between unit, integration, and system tests, check out the Wikipedia article on testing.

Naming Rules ↟

Keep in mind that your tests will be compiled to .beam and then run with Erlang's eunit module. As such, your tests need to following the same conventions that eunit establishes:

• Test module filenames should end in -tests, e.g., some-module-tests.lfe.

• Test module and filename need to be the same, minus the extension. For example, test/unit-my-module-tests.lfe needs to be declared as (defmodule unit-my-module-tests ...) in the test case module.

• If you chose not to use the deftest macro to build each unit test function, you will need to name your unit test functions with _test appended to them. For example, (defun unit-my-function-negagive-check_test () ...). We recommend, however, that you use deftest instead, and obviate the need for _test () boilerplate.

Creating Unit Tests ↟

ltest is entirely macro-based. ltest uses LFE to parse the Erlang macros in the eunit header file. It also provides its own header file which defines macros whose main purpose is to wrap the eunit macros in a more Lispy form.

ltest also provides a syntactic sugar macro for defining tests: deftest. Instead of writing something like this for your unit tests:

    (defun unit-my-function-test ()
      ...)

You can use deftest to write this:

    (deftest unit-my-function
      ...)

Note that the -test is no longer needed, nor is the empty argument list.

If you would like to use EUnit's fixtures feature, you must use another macro:

    (deftestgen unit-my-function
      ...)

See the unit tests in the test directory for example usage.

If you would like tests to be skipped, you can use this macro:

    (deftestskip unit-my-function
      ...)

This will simply make the test invisible to EUnit. EUnit doesn't actually track user-skipped tests; it only tracks tests that are skipped do to issues as perceived by EUnit.

However, ltest's test runner does track skipped tests and will report these in its output.

Here is a more complete example:

    (defmodule unit-mymodule-tests
      (behaviour ltest-unit)
      (export all)
      (import
        (from ltest
          (check-failed-assert 2)
          (check-wrong-assert-exception 2))))

    (include-lib "deps/ltest/include/ltest-macros.lfe")

    (deftest is
      (is 'true)
      (is (not 'false))
      (is (not (not 'true))))

    (deftest is-not
      (is-not `'false))

    (deftest is-equal
      (is-equal 2 (+ 1 1)))

ltest is working towards full test coverage; while not there yet, the unit tests for ltest itself provide the best examples of usage.

Running Your Tests ↟

The recommended way to run unit tests is to use lfetool. Running unit tests is now as easy as doing the following:

    $ lfetool tests build
    $ lfetool tests unit

Similarly, if your project has defined integration tests, you can do:

    $ lfetool tests integration

If you'd like to run unit, integration, and system tests together, run the following:

    $ lfetool tests all

The LFE Test Runner ↟

ltest now includes a test runner which overrides the EUnit handlers with its own. The original (and currently used) test runner functionality in lfetool is actually a series of gross shell hacks around the verbose EUnit test runner. More sed and manual ANSI terminal colors than is healthy for anyone.

The new test runner code in ltest let's you skip that madness. For example, this project has a make target that uses it:

check-runner-eunit: compile-no-deps compile-tests
    @PATH=$(SCRIPT_PATH) ERL_LIBS=$(ERL_LIBS) \
    erl -cwd "`pwd`" -listener eunit_progress -eval \
    "case 'ltest-runner':all() of ok -> halt(0); _ -> halt(127) end" \
    -noshell

Here's what the output looks like with failing and skipped tests:

End:

And here's what passing tests looks like:

End:

The rest of the make targets still use lfetool, and will continue to do so, since lfetool will be updating to use ltest's new runner. If you'd like to track the progress on these, here are the related tickets:

• lfe-deprecated/ltool#4
• lfe-deprecated/lfetool#160

Dogfood ↟

ltest writes its unit tests in ltest :-) You can run them from the project directory:

    $ make check

Which will give you output similar to the following:

    ------------------
    Running unit tests ...
    ------------------

    ======================== EUnit ========================
    module 'ltest-basic-tests'
      is ............................................. [ok]
      is-with-one-phrase-deftest ..................... [ok]
      is-with-two-phrase-deftest ..................... [ok]
      is-with-many-phrase-deftest .................... [ok]
      is-fail .............................. [0.003 s] [ok]
      is-not ......................................... [ok]
      is-not-fail .................................... [ok]
      is-equal ....................................... [ok]
      is-equal-fail .................................. [ok]
      is-not-equal ................................... [ok]
      is-not-equal-fail .............................. [ok]
      is-exception ................................... [ok]
      is-exception-wrong-class ....................... [ok]
      is-exception-wrong-term ........................ [ok]
      is-exception-unexpected-success ................ [ok]
      is-error ....................................... [ok]
      is-error-wrong-term ............................ [ok]
      is-error-unexpected-success .................... [ok]
      is-throw ....................................... [ok]
      is-throw-wrong-term ............................ [ok]
      is-throw-unexpected-success .................... [ok]
      is-exit ........................................ [ok]
      is-exit-wrong-term ............................. [ok]
      is-exit-unexpected-success ..................... [ok]
      is-match ....................................... [ok]
      is-match-fail .................................. [ok]
      Total module test time: 0.081 s
    module 'ltest-fixture-tests'
      setup-test-case ................................ [ok]
      setup-test-case ................................ [ok]
      setup-test-case ................................ [ok]
      setup-test-case ................................ [ok]
      setup-test-case ................................ [ok]
      setup-test-case ................................ [ok]
      foreach-test-case .............................. [ok]
      foreach-test-case .............................. [ok]
      setup-test-case ................................ [ok]
      setup-test-case ................................ [ok]
      foreach-test-case .............................. [ok]
      foreach-test-case .............................. [ok]
      Total module test time: 0.035 s
    module 'ltest-generated-tests'
      one-lambda ..................................... [ok]
      one-lambda-in-list ............................. [ok]
      many-lambdas-in-list ........................... [ok]
      many-lambdas-in-list ........................... [ok]
      many-lambdas-in-list ........................... [ok]
      lambda-with-nested-testset ..................... [ok]
      Total module test time: 0.017 s
    module 'ltest-named-tests'
      named-is ....................................... [ok]
      named-is-not-fail .............................. [ok]
      named-testset-with-one ......................... [ok]
      named-testset-with-two ......................... [ok]
      named-testset-with-three ....................... [ok]
      named-testset-nested ........................... [ok]
      named-testset-deeply-nested .................... [ok]
      Total module test time: 0.021 s
    module 'ltest-testset-tests'
      testset-with-one ............................... [ok]
      testset-with-two ............................... [ok]
      testset-with-three ............................. [ok]
      testset-nested ................................. [ok]
      testset-deeply-nested .......................... [ok]
      Total module test time: 0.015 s
    =======================================================
      All 56 tests passed.