MOxUnit is a lightweight unit test framework for Matlab and GNU Octave.

• Features
• Installation
• Defining MOxUnit tests
• Running MOxUnit tests
• Use with CI
  • Octave
  • Matlab
• Compatibility notes
• Limitations

• Runs on both the Matlab and GNU Octave platforms.
• Uses object-oriented TestCase, TestSuite and TestResult classes, allowing for user-defined extensions.
• Can be used directly with continuous integration services, such as Travis-ci and Shippable.
• Supports JUnit-like XML output for use with Shippable and other test results visualization approaches.
• Supports the generation of code coverage reports using MOCov
• Provides compatibility with the (now unsupported) Steve Eddin's Matlab xUnit test framework, and with recent Matlab test functionality.
• Distributed under the MIT license, a permissive free software license.

• Using the shell (requires a Unix-like operating system such as GNU/Linux or Apple OSX):

  git clone https://github.com/MOxUnit/MOxUnit.git
  cd MOxUnit
  make install

  This will add the MOxUnit directory to the Matlab and/or GNU Octave searchpath. If both Matlab and GNU Octave are available on your machine, it will install MOxUnit for both.

• Manual installation:

  • Download the [MOxUnit zip archive from the MOxUnit website, and extract it. This should result in a directory called MOxUnit-master.

  • Start Matlab or GNU Octave.

  • On the Matlab or GNU Octave prompt, go to the directory that contains the new MOxUnit-master directory, then run:

    % change to the MOxUnit subdirectory
    %
    % Note: if MOxUnit was retrieved using 'git', then the name of
    %       top-level directory is 'MOxUnit', not 'MOxUnit-master'
    cd MOxUnit-master/MOxUnit
    
    % add the current directory to the Matlab/GNU Octave path
    moxunit_set_path()
    
    % save the path
    savepath

To define unit tests, write a function with the following header:

function test_suite=test_of_abs
    try % assignment of 'localfunctions' is necessary in Matlab >= 2016
        test_functions=localfunctions();
    catch % no problem; early Matlab versions can use initTestSuite fine
    end
    initTestSuite;

• It is crucial that the output of the main function is a variable named test_suite, and that the output of localfunctions is assigned to a variable named test_functions.
• As of Matlab 2016b, Matlab scripts (such as initTestSuite.m) do not have access to subfunctions in a function if called from that function. Therefore it requires using localfunctions to obtain function handles to local functions. The "try-catch-end" statements are necessary for compatibility with older versions of GNU Octave, which do not provide the localfunctions function.
• Alas, the call to localfunctions cannot be incorporated into initTestSuite so the entire code snippet above has to be the header of each test file

Then, define subfunctions whose name start with test or end with test (case-insensitive). These functions can use the following assert* functions:

• assertTrue(a): assert that a is true.
• assertFalse(a): assert that a is false.
• assertEqual(a,b): assert that a and b are equal.
• assertElementsAlmostEqual(a,b): assert that the floating point arrays a and b have the same size, and that corresponding elements are equal within some numeric tolerance.
• assertVectorsAlmostEqual(a,b): assert that floating point vectors a and b have the same size, and are equal within some numeric tolerance based on their vector norm.
• assertExceptionThrown(f,id): assert that calling f() throws an exception with identifier id. (To deal with cases where Matlab and GNU Octave throw errors with different identifiers, use moxunit_util_platform_is_octave. Or use id='*' to match any identifier).

As a special case, moxunit_throw_test_skipped_exception('reason') throws an exception that is caught when running the test; moxunit_run_tests will report that the test is skipped for reason reason.

For example, the following function defines three unit tests that tests some possible inputs from the builtin abs function:

function test_suite=test_of_abs
    try % assignment of 'localfunctions' is necessary in Matlab >= 2016
        test_functions=localfunctions();
    catch % no problem; early Matlab versions can use initTestSuite fine
    end
    initTestSuite;

function test_abs_scalar
    assertTrue(abs(-1)==1)
    assertEqual(abs(-NaN),NaN);
    assertEqual(abs(-Inf),Inf);
    assertEqual(abs(0),0)
    assertElementsAlmostEqual(abs(-1e-13),0)

function test_abs_vector
    assertEqual(abs([-1 1 -3]),[1 1 3]);

function test_abs_exceptions
    % GNU Octave and Matlab use different error identifiers
    if moxunit_util_platform_is_octave()
        assertExceptionThrown(@()abs(struct),'');
    else
        assertExceptionThrown(@()abs(struct),...
                             'MATLAB:UndefinedFunction');
    end

Examples of unit tests are in MOxUnit's tests directory, which test some of MOxUnit's functions itself.

• cd to the directory where the unit tests reside. For MOxUnit itself, the unit tests are in the directory tests.

• run the tests using moxunit_runtests. For example, running moxunit_runtests from MOxUnit's tests directory runs tests for MOxUnit itself, and should give the following output:

  >> moxunit_runtests
  suite: 98 tests
  ............................................................
  ......................................
  --------------------------------------------------
  
  OK (passed=98)
  ans =
    logical
    1

• moxunit_runtests, by default, gives non-verbose output and runs all tests in the current directory. This can be changed using the following arguments:

  • -verbose: show verbose output.
  • -quiet: suppress all output
  • directory: run unit tests in directory directory.
  • file.m: run unit tests in file file.m.
  • -recursive: add files from directories recursively.
  • -logfile logfile.txt: store the output in file logfile.txt.
  • -junit_xml_file xmlfile: store JUnit-like XML output in file xmlfile.

• To test MOxUnit itself from a terminal, run:

  make test
  

MOxUnit can be used with the Travis-ci service for continuous integration (CI) testing. This is achieved by setting up a .travis.yml configuration file. This file is also used by Shippable. As a result, the test suite is run automatically on both Travis-ci and Shippable every time it is pushed to the github repository, or when a pull request is made. If a test fails, or if all tests pass after a test failed before, the developers are notified by email.

The easiest test to set up on Travis and/or Shippable is with GNU Octave. Make sure your code is Octave compatible. Note that many Matlab projects tend to use functionality not present in Octave (such as particular functions), whereasand writing code that is both Matlab- and Octave-compatible may require some additional efforts.

A simple .travis.yml file for a project could look like that:

language: generic
os: linux
      
before_install:
  - sudo apt-get install octave

before_script:
  - git clone https://github.com/MOxUnit/MOxUnit.git
  - make -C MOxUnit install

script:        
  - make test

In this case make test is used to run the tests. To avoid a Makefile and run tests directly through Octave, the script has to call Octave directly to run the tests:

# ...
before_script:
- git clone https://github.com/MOxUnit/MOxUnit.git

script:
  - octave --no-gui --eval "addpath('~/git/MOxUnit/MOxUnit');moxunit_set_path;moxunit_runtests('tests')"

Note that MOxUnit tests itself on travis, with this travis file.

Travis now supports Matlab directly. You can use MOxUnit with it, but its tricky because:

1. Travis only supports Matlab 2020a and, presumably, higher (at the time of writing 2020a is the newest version).
2. Makefile installation does not work with Matlab on travis.
3. Nor does calling Matlab from the command line in a usual way - with matlab -nodesktop -nosplash ... . Instead it has to be called with the -batch flag.

Therefore, .travis.yml file looks as follows:

language: matlab
matlab: R2020a
os: linux

# Just clone MOxUnit, `don't make install` it (!)
before_script:
  - git clone https://github.com/MOxUnit/MOxUnit.git
    
script: 
  - matlab -batch 'back=cd("./MOxUnit/MOxUnit/"); moxunit_set_path(); cd(back); moxunit_runtests tests -verbose; exit(double(~ans))'

exit(double(~ans)) ensures that the build fails if MOxUnit tests fail.

• Because GNU Octave 3.8 does not support classdef syntax, 'old-style' object-oriented syntax is used for the class definitions. For similar reasons, MOxUnit uses the lasterror function, even though its use in Matlab is discouraged.

• Recent versions of Matlab (2016 and later) do not support tests defined just using "initTestSuite", that is without the use of localfunctions (see above). To ease the transition, consider using the Python script tools/fix_mfile_test_init.py, which can update existing .m files that do not use localfunctions.

  For example, the following command was used on a Unix-like shell to preview changes to MOxUnit's tests:

    find tests -iname 'test*.m' | xargs -L1 tools/fix_mfile_test_init.py

  and adding the --apply option applies these changes, meaning that found files are rewritten:

    find tests -iname 'test*.m' | xargs -L1 tools/fix_mfile_test_init.py --apply

• Recent versions of Matlab define a matlab.unittest.Test class for unit tests. An instance t can be used with MOxUnit using the MOxUnitMatlabUnitWrapperTestCase(t), which is a MOxUnitTestCase instance. Tests that are defined through

  function tests=foo()
      tests=functiontests(localfunctions)
  
  function test_funcA(param)
  
  function test_funcA(param)

  can be run using MOxUnit as well (and included in an MOxUnitTestSuite instance using its with addFile) instance, with the exception that currently setup and teardown functions are currently ignored.

Currently MOxUnit does not support:

• Documentation tests require MOdox.
• Support for setup and teardown functions in TestCase classes.
• Subclasses of MOxUnit's classes (MOxUnitTestCase, MOxUnitTestSuite, MOxUnitTestReport) have to be defined using "old-style" object-oriented syntax.
• Subtests

• The object-oriented class structure was inspired by the Python unit test framework.
• The assert* function signatures are aimed to be compatible with Steve Eddin's Matlab xUnit test framework.

Nikolaas N. Oosterhof, n dot n dot oosterhof at googlemail dot com.

• Thanks to Scott Lowe, Thomas Feher, Joel LeBlanc, Anderson Bravalheri, Sven Baars, 'jdbancal', Marcin Konowalczyk for contributions.