--- /dev/null
+<?php
+
+namespace Drupal\Tests\Listeners;
+
+use Drupal\KernelTests\KernelTestBase;;
+use Drupal\Tests\BrowserTestBase;;
+use Drupal\Tests\UnitTestCase;
+use PHPUnit\Framework\AssertionFailedError;
+
+/**
+ * Ensures that no component tests are extending a core test base class.
+ *
+ * @internal
+ */
+trait DrupalComponentTestListenerTrait {
+
+ /**
+ * Reacts to the end of a test.
+ *
+ * @param \PHPUnit\Framework\Test|\PHPUnit_Framework_Test $test
+ * The test object that has ended its test run.
+ * @param float $time
+ * The time the test took.
+ */
+ protected function componentEndTest($test, $time) {
+ /** @var \PHPUnit\Framework\Test $test */
+ if (substr($test->toString(), 0, 22) == 'Drupal\Tests\Component') {
+ if ($test instanceof BrowserTestBase || $test instanceof KernelTestBase || $test instanceof UnitTestCase) {
+ $error = new AssertionFailedError('Component tests should not extend a core test base class.');
+ $test->getTestResultObject()->addFailure($test, $error, $time);
+ }
+ }
+ }
+
+}