PHPUnit

Drupal 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.

Important note:

In 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. Remember not to do this in 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 the tests using the command line instead. Actually, it's very easy to do so. To run an entire test suite (of a certain type), we have to navigate to the Drupal core folder (this works in a normal Drupal site installation where the vendor folder is located there):

cd core  

And run the following command:

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

This command goes back a folder through...