class TestSuiteBase

abstract class TestSuiteBase extends TestSuite {
  
  /**
   * Finds extensions in a Drupal installation.
   *
   * An extension is defined as a directory with an *.info.yml file in it.
   *
   * @param string $root
   *   Path to the root of the Drupal installation.
   *
   * @return string[]
   *   Associative array of extension paths, with extension name as keys.
   */
  protected function findExtensionDirectories($root) {
    $extension_roots = \drupal_phpunit_contrib_extension_directory_roots($root);
    $extension_directories = array_map('drupal_phpunit_find_extension_directories', $extension_roots);
    return array_reduce($extension_directories, 'array_merge', []);
  }
  
  /**
   * Find and add tests to the suite for core and any extensions.
   *
   * @param string $root
   *   Path to the root of the Drupal installation.
   * @param string $suite_namespace
   *   SubNamespace used to separate test suite. Examples: Unit, Functional.
   */
  protected function addTestsBySuiteNamespace($root, $suite_namespace) {
    // Core's tests are in the namespace Drupal\{$suite_namespace}Tests\ and are
    // always inside of core/tests/Drupal/{$suite_namespace}Tests. The exception
    // to this is Unit tests for historical reasons.
    if ($suite_namespace == 'Unit') {
      $tests = TestDiscovery::scanDirectory("Drupal\\Tests\\", "{$root}/core/tests/Drupal/Tests");
      $tests = array_flip(array_filter(array_flip($tests), function ($test_class) {
        // The Listeners directory does not contain tests. Use the class name
        // to be compatible with all operating systems.
        return !preg_match('/^Drupal\\\\Tests\\\\Listeners\\\\/', $test_class);
      }));
      $this->addTestFiles($tests);
    }
    else {
      $this->addTestFiles(TestDiscovery::scanDirectory("Drupal\\{$suite_namespace}Tests\\", "{$root}/core/tests/Drupal/{$suite_namespace}Tests"));
    }
    // Extensions' tests will always be in the namespace
    // Drupal\Tests\$extension_name\$suite_namespace\ and be in the
    // $extension_path/tests/src/$suite_namespace directory. Not all extensions
    // will have all kinds of tests.
    foreach ($this->findExtensionDirectories($root) as $extension_name => $dir) {
      $test_path = "{$dir}/tests/src/{$suite_namespace}";
      if (is_dir($test_path)) {
        $this->addTestFiles(TestDiscovery::scanDirectory("Drupal\\Tests\\{$extension_name}\\{$suite_namespace}\\", $test_path));
      }
    }
  }

}