title: Run phpunit tests by testcase class that they extend
body: <p>I want to separate my tests in unit and integration tests and have an abstract TestCase class for each, e.g. <code>UnitTestCase</code> and <code>IntegrationTestCase</code>.</p>
  
  <p>Is there a nice way to run only those tests that extend <code>UnitTestCase</code> without giving a <code>@group unit</code> annotation to each of these test classes?</p>
  
  <p>The <a href="https://phpunit.readthedocs.io/en/8.1/extending-phpunit.html#subclass-phpunit-framework-testcase" rel="nofollow noreferrer">phpunit documentation</a> is very sparse when describing subclassing. Also a google search didn't turn up any useful results.</p>