Manual:JavaScript unit testing

Unit testing in MediaWiki for its JavaScript code base is performed using the QUnit JavaScript Testing framework..

The unit tests in core are located in the  directory. Tests are organised into a directory structure that matches the directory structure of the code that they are testing. For example: The unit tests for file resources/mediawiki.util/mediawiki.util.js can be found in tests/qunit/suites/resources/mediawiki.util/mediawiki.util.test.js.

Extensions add their QUnit tests on the ResourceLoaderTestModules hook.

Running the unit tests


Unit tests are run from the browser. To do so:
 * 1) Set  to.
 * 2) Go to  on your wiki and select the framework of choice, or go to  directly
 * 3) No step 3, tests are being run now!

With some effort you can also run QUnit tests from the command-line in a headless browser like PhantomJS. The VisualEditor extension uses node.js to do this.

Options



 * Available skins: On top is a drop down menu to switch active Skin. Selecting a skin will refresh the page and set the chosen skin via the   query parameter to index.php.
 * noglobals: Core URL parameter of QUnit
 * notrycatch: Core URL parameter of QUnit
 * debug: Toggle debug mode of ResourceLoader
 * completenesstest: Whether or not to load jQuery QUnit CompletenessTest.
 * mwlogenv: When enabled, environment setup and teardown will be logged to the console.
 * Module: Select a module from the list to immediately run it.

You can supply a query string parameter  to the URL and QUnit will only run modules matching string (case-insensitive); prepend   to the string to exclude modules matching string.

Run tests before committing
Make it a habit to run unit tests before committing and submitting your changes to Gerrit. Any problems that you didn't cause? See if you can find a cause and let the committer know by leaving a comment in Gerrit.

Write unit tests
Always provide unit tests for new functionality. We're also looking to expand our unit test coverage of already existing modules in the MediaWiki JavaScript library. Run the CompletenessTest and find out which methods don't have unit tests yet and write one.

Write a unit test

 * TODO: Incomplete


 * The file should be named after the module (or file) it is testing.

QUnit

 * Inside the test suite file should be one, and one exactly, call  with the filename as module name (but without the .test.js suffix). This is to enable sectioning in the QUnit output and to allow executing each module separately.

MediaWiki core
Core test suites need to be added to the registration of the  module. Do so in QUnitTestResources.php (in ./tests/qunit/).

So if you created a test suite for, then that test suite should be stored in ./tests/qunit/suites/resources/mediawiki/mediawiki.foobar.test. Then you would add that file path to the "scripts" array. And, unless already, add the  module as a dependency (since that module must be loaded before the test suite can run).

Extensions
Extensions need to register their tests suits as a module. See Manual:Hooks/ResourceLoaderTestModules for more details.

Tips

 * The tests should work in all language environments, but sometimes may fail if $wgLanguageCode is not "en". If your wiki's language is not "en" and tests fail mysteriously, try changing $wgLanguageCode to "en" and running the tests, and then try with your language again.