PHPUnit

Drupal 8 uses PHPUnit as the testing framework for all types of tests. In this section, we will see how we can work with it to run tests.

On your development environment (or wherever you want to run the tests), make sure you have the composer dependencies installed with the --dev flag. This will include PHPUnit. Keep in mind not to ever do this on your production environment as you can compromise the security of your application.

Although Drupal has a UI for running tests, PHPUnit is not well integrated with this. So, it's recommended that we run them using the command line instead. Actually, it's very easy to do so. To run the entire test suite (of a certain type), we have to navigate to the Drupal core folder:

cd core  

And run the following command:

../vendor/bin/phpunit —testsuite=unit  

This command goes back a folder through the vendor directory and uses the installed phpunit executable. As an option, in the previous example, we specified that we only want to run unit tests. Omitting that would run all types of tests. However, for most of the others, there will be some configuration needed, as we will see in the respective sections.

If we want to run a specific test, we can pass it as an argument to the phpunit command (the path to the file):

../vendor/bin/phpunit tests/Drupal/Tests/Core/Routing/UrlGeneratorTest.php  

In this example, we run a Drupal core test that tests the UrlGenerator class.

Alternatively, we can run multiple tests that belong to the same group (we will see how tests are added to a group soon):

../vendor/bin/phpunit —group=Routing 

This runs all the tests from the Routing group which actually contains the UrlGeneratorTest we saw earlier. We can run tests from multiple groups if we separate them by a comma.

Also, to check what the available groups are, we can run the following command:

../vendor/bin/phpunit —list-groups 

This will list all the groups that have been registered with PHPUnit.

Finally, we can also run a specific method found inside a test by using the —filter argument:

../vendor/bin/phpunit —filter=testAliasGenerationUsingInterfaceConstants  

This is one of the test methods from the same UrlGeneratorTest we saw before and is the only one that would run.