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 tests/qunit 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

If all goes well, the tests will quickly run and show a green bar at the top like this.

Unit tests are run from the browser. To do so:

1. Set $wgEnableJavaScriptTest to true.
2. Go to Special:JavaScriptTest on your wiki and select the framework of choice, or go to Special:JavaScriptTest/qunit 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

Example of what a CompletenessTest report looks like.

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 useskin 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 filter=string to the URL and QUnit will only run modules matching string (case-insensitive); prepend ! to the string to exclude modules matching string.

How to help?

Run tests before committing

Make it a habit to run unit tests before committing your 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 QUnit.module() 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.

How to register a test suite

MediaWiki core

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

So if you created a test suite for mediawiki.foobar, 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 mediawiki.foobar module as a dependency (since that module must be loaded before the test suite can run).

 'mediawiki.tests.qunit.suites' => array(
 	'scripts' => array(
 		'tests/qunit/suites/resources/mediawiki/mediawiki.test.js',
+		'tests/qunit/suites/resources/mediawiki/mediawiki.foobar.test.js',
 		'tests/qunit/suites/resources/mediawiki/mediawiki.user.test.js',
 		'tests/qunit/suites/resources/mediawiki/mediawiki.util.test.js',
 	),
 	'dependencies' => array(
 		'mediawiki',
+		'mediawiki.foobar',
 		'mediawiki.user',
 		'mediawiki.util',

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.

See also

• Manual:Writing testable JavaScript
• Manual:Hooks/ResourceLoaderTestModules
• Manual:JavaScript unit testing/QUnit guidelines