diff --git a/core/lib/Drupal/Core/Test/EnvironmentCleaner.php b/core/lib/Drupal/Core/Test/EnvironmentCleaner.php
index 022451669a..23976b666c 100644
--- a/core/lib/Drupal/Core/Test/EnvironmentCleaner.php
+++ b/core/lib/Drupal/Core/Test/EnvironmentCleaner.php
@@ -3,8 +3,7 @@
 namespace Drupal\Core\Test;
 
 use Drupal\Core\Database\Connection;
-use Drupal\Core\StringTranslation\TranslationInterface;
-use Drupal\Core\File\FileSystem;
+use Drupal\Core\File\FileSystemInterface;
 use Symfony\Component\Console\Output\OutputInterface;
 
 /**
@@ -38,7 +37,7 @@ class EnvironmentCleaner implements EnvironmentCleanerInterface {
   /**
    * The file system service.
    *
-   * @var \Drupal\Core\File\FileSystem
+   * @var \Drupal\Core\File\FileSystemInterface
    */
   protected $fileSystem;
 
@@ -53,16 +52,17 @@ class EnvironmentCleaner implements EnvironmentCleanerInterface {
    *
    * @param string $root
    *   The path to the root of the Drupal installation.
-   * @param Connection $test_database
+   * @param \Drupal\Core\Database\Connection $test_database
    *   Connection to the database against which tests were run.
-   * @param Connection $results_database
+   * @param \Drupal\Core\Database\Connection $results_database
    *   Connection to the database where test results were stored. This could be
    *   the same as $test_database, or it could be different.
-   * @param TranslationInterface|null $translation
-   *   (optional) The translation service. If none is supplied, this class will
-   *   attempt to discover one using \Drupal.
+   * @param \Symfony\Component\Console\Output\OutputInterface $output
+   *   A symfony console output object.
+   * @param \Drupal\Core\File\FileSystemInterface $file_system
+   *   The file_system service.
    */
-  public function __construct($root, Connection $test_database, Connection $results_database, OutputInterface $output, FileSystem $file_system) {
+  public function __construct($root, Connection $test_database, Connection $results_database, OutputInterface $output, FileSystemInterface $file_system) {
     $this->root = $root;
     $this->testDatabase = $test_database;
     $this->resultsDatabase = $results_database;
diff --git a/core/lib/Drupal/Core/Test/EnvironmentCleanerInterface.php b/core/lib/Drupal/Core/Test/EnvironmentCleanerInterface.php
index c7f2fd48ab..8ab6681de4 100644
--- a/core/lib/Drupal/Core/Test/EnvironmentCleanerInterface.php
+++ b/core/lib/Drupal/Core/Test/EnvironmentCleanerInterface.php
@@ -3,6 +3,7 @@
 namespace Drupal\Core\Test;
 
 interface EnvironmentCleanerInterface {
+
   /**
    * Removes all test-related database tables and directories.
    *
diff --git a/core/modules/simpletest/src/EnvironmentCleanerFactory.php b/core/modules/simpletest/src/EnvironmentCleanerFactory.php
index c04e888a04..dc48b50a21 100644
--- a/core/modules/simpletest/src/EnvironmentCleanerFactory.php
+++ b/core/modules/simpletest/src/EnvironmentCleanerFactory.php
@@ -24,7 +24,7 @@ class EnvironmentCleanerFactory {
   /**
    * Construct an environment cleaner factory.
    *
-   * @param Container $container
+   * @param \Drupal\Core\DependencyInjection\Container $container
    *   The container.
    */
   public function __construct(Container $container) {
diff --git a/core/modules/simpletest/src/EnvironmentCleanerService.php b/core/modules/simpletest/src/EnvironmentCleanerService.php
index 33b7734ace..751bad1ad5 100644
--- a/core/modules/simpletest/src/EnvironmentCleanerService.php
+++ b/core/modules/simpletest/src/EnvironmentCleanerService.php
@@ -48,12 +48,12 @@ class EnvironmentCleanerService extends EnvironmentCleaner {
    *
    * @param string $root
    *   The path to the root of the Drupal installation.
-   * @param Connection $test_database
+   * @param \Drupal\Core\Database\Connection $test_database
    *   Connection to the database against which tests were run.
-   * @param Connection $results_database
+   * @param \Drupal\Core\Database\Connection $results_database
    *   Connection to the database where test results were stored. This could be
    *   the same as $test_database, or it could be different.
-   * @param TranslationInterface|null $translation
+   * @param \Drupal\Core\StringTranslation\TranslationInterface|null $translation
    *   (optional) The translation service. If none is supplied, this class will
    *   attempt to discover one using \Drupal.
    */