Drupal 8: Execute automated tests and debug them in PhpStorm

To test Drupal 8 tests by the command line, you need to do the following. You need to export two environment variables first:

export SIMPLETEST_DB=mysql://root:password@localhost/database;
export SIMPLETEST_BASE_URL=http://host;

Then you can execute the test by the following command, being in the Drupal root folder:

vendor/bin/phpunit -c core modules/my_module/tests/src/Kernel/MyTest.php

Make sure to set the environment variable for PhpStorm:

export XDEBUG_CONFIG="remote_enable=1 remote_mode=req remote_port=9000 remote_host=127.0.0.1 remote_connect_back=0"

phpunit.xml 

There's a phpunit.xml.dist file in PHP projects. That's a template for your PHPUnit configuration. You can specifiy there some PHP ini settings. By this method you do not need to export the variables like above. Copy it to phpunit.xml and set there your settings like follows:

Afterwards you are able to run your test without the manual environment variables setting, just by specifying your configuration directory by the "-c" parameter. Example:

vendor/bin/phpunit -c modules/permissions_by_term modules/permissions_by_term/tests/src/Kernel/SelectTermTest.php

This command cannot execute SimpleTest tests, which inherit from the WebTestBase class. Only unit tests and tests which inherits from the KernelTestBase class can be run.

Runs a SimpleTest

// --- SimpleTests
php core/scripts/run-tests.sh --url http://d8-paragraphs:8888 --browser --verbose --color --concurrency 4 --class 'Drupal\paragraphs\Tests\ParagraphsPreviewTest'

Troubleshooting

If the debug mode is switched on in PhpStorm and the debugger does not stop at the breakpoint and you are getting the following output in the debugger window:

Remote file path '/home/user/Websites/my-project/-' is not mapped to any file path in project

If you have already setup path mapping, then there's probably any error in your code. Chances are, that it is in the first line of the setUp() method of your test class, which inherits from KernelTestBase. Then you probably do not have Drupal 8.2.x but Drupal 8.1.x. If it's in the first line, you can insert any code line or insert

xdebug_break(); 

With this function the debugger will be forced to stop on a specific line.

PhpStorm IDE settings (version 2016.1.2)

If you are executing the tests from the command line (and probably also via the IDE itself) it's important that you setup the path mappings, so that Xdebug can recognize your test's location. You can to this in PhpStorm's settings at "Languages & Frameworks > PHP > Servers". Create a host for your Drupal website host and set the path mapping to your tests directory. An example you can find in the screenshot below: