--- /dev/null
+<?php
+
+namespace Drupal\Tests\simpletest\Kernel;
+
+use Drupal\KernelTests\KernelTestBase;
+
+/**
+ * @group simpletest
+ * @group legacy
+ *
+ * @coversDefaultClass \Drupal\simpletest\TestDiscovery
+ */
+class TestDiscoveryDeprecationTest extends KernelTestBase {
+
+ /**
+ * {@inheritdoc}
+ */
+ public static $modules = ['simpletest', 'simpletest_deprecation_test'];
+
+ /**
+ * @expectedDeprecation The deprecated alter hook hook_simpletest_alter() is implemented in these functions: simpletest_deprecation_test_simpletest_alter. Convert your test to a PHPUnit-based one and implement test listeners. See: https://www.drupal.org/node/2939892
+ * @covers ::getTestClasses
+ */
+ public function testHookSimpletestAlter() {
+ // The simpletest_test module implements hook_simpletest_alter(), which
+ // should trigger a deprecation error during getTestClasses().
+ $this->assertNotEmpty(
+ $this->container->get('test_discovery')->getTestClasses()
+ );
+ }
+
+}