diff --git a/core/modules/config/src/Controller/ConfigController.php b/core/modules/config/src/Controller/ConfigController.php
index 7900ed7..dd1208b 100644
--- a/core/modules/config/src/Controller/ConfigController.php
+++ b/core/modules/config/src/Controller/ConfigController.php
@@ -17,11 +17,13 @@
 use Drupal\system\FileDownloadController;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\HttpFoundation\Request;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * Returns responses for config module routes.
  */
 class ConfigController implements ContainerInjectionInterface {
+  use StringTranslationTrait;
 
   /**
    * The target storage.
@@ -136,7 +138,7 @@ public function diff($source_name, $target_name = NULL, $collection = NULL) {
 
     $build = array();
 
-    $build['#title'] = t('View changes of @config_file', array('@config_file' => $source_name));
+    $build['#title'] = $this->t('View changes of @config_file', array('@config_file' => $source_name));
     // Add the CSS for the inline diff.
     $build['#attached']['library'][] = 'system/diff';
 
@@ -146,8 +148,8 @@ public function diff($source_name, $target_name = NULL, $collection = NULL) {
         'class' => array('diff'),
       ),
       '#header' => array(
-        array('data' => t('Active'), 'colspan' => '2'),
-        array('data' => t('Staged'), 'colspan' => '2'),
+        array('data' => $this->t('Active'), 'colspan' => '2'),
+        array('data' => $this->t('Staged'), 'colspan' => '2'),
       ),
       '#rows' => $this->diffFormatter->format($diff),
     );
diff --git a/core/modules/config/src/Form/ConfigSync.php b/core/modules/config/src/Form/ConfigSync.php
index 03de002..014f299 100644
--- a/core/modules/config/src/Form/ConfigSync.php
+++ b/core/modules/config/src/Form/ConfigSync.php
@@ -341,10 +341,10 @@ public function submitForm(array &$form, FormStateInterface $form_state) {
         $batch = array(
           'operations' => array(),
           'finished' => array(get_class($this), 'finishBatch'),
-          'title' => t('Synchronizing configuration'),
-          'init_message' => t('Starting configuration synchronization.'),
-          'progress_message' => t('Completed @current step of @total.'),
-          'error_message' => t('Configuration synchronization has encountered an error.'),
+          'title' => $this->t('Synchronizing configuration'),
+          'init_message' => $this->t('Starting configuration synchronization.'),
+          'progress_message' => $this->t('Completed @current step of @total.'),
+          'error_message' => $this->t('Configuration synchronization has encountered an error.'),
           'file' => drupal_get_path('module', 'config') . '/config.admin.inc',
         );
         foreach ($sync_steps as $sync_step) {
diff --git a/core/modules/config/src/Tests/ConfigDependencyWebTest.php b/core/modules/config/src/Tests/ConfigDependencyWebTest.php
index af63fed..0eaa324 100644
--- a/core/modules/config/src/Tests/ConfigDependencyWebTest.php
+++ b/core/modules/config/src/Tests/ConfigDependencyWebTest.php
@@ -9,6 +9,7 @@
 
 use Drupal\Core\Config\Entity\ConfigEntityStorage;
 use Drupal\simpletest\WebTestBase;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * Tests configuration entities.
@@ -16,6 +17,7 @@
  * @group config
  */
 class ConfigDependencyWebTest extends WebTestBase {
+  use StringTranslationTrait;
 
   /**
    * The maximum length for the entity storage used in this test.
@@ -64,11 +66,11 @@ function testConfigDependencyDeleteFormTrait() {
     $entity2->save();
 
     $this->drupalGet($entity2->urlInfo('delete-form'));
-    $this->assertNoText(t('Configuration updates'), 'No configuration updates found.');
-    $this->assertNoText(t('Configuration deletions'), 'No configuration deletes found.');
+    $this->assertNoText($this->t('Configuration updates'), 'No configuration updates found.');
+    $this->assertNoText($this->t('Configuration deletions'), 'No configuration deletes found.');
     $this->drupalGet($entity1->urlInfo('delete-form'));
-    $this->assertNoText(t('Configuration updates'), 'No configuration updates found.');
-    $this->assertText(t('Configuration deletions'), 'Configuration deletions found.');
+    $this->assertNoText($this->t('Configuration updates'), 'No configuration updates found.');
+    $this->assertText($this->t('Configuration deletions'), 'Configuration deletions found.');
     $this->assertText($entity2->id(), 'Entity2 id found');
     $this->drupalPostForm($entity1->urlInfo('delete-form'), array(), 'Delete');
     $storage->resetCache();
@@ -115,8 +117,8 @@ function testConfigDependencyDeleteFormTrait() {
     $entity3->save();
 
     $this->drupalGet($entity1->urlInfo('delete-form'));
-    $this->assertText(t('Configuration updates'), 'Configuration updates found.');
-    $this->assertNoText(t('Configuration deletions'), 'No configuration deletions found.');
+    $this->assertText($this->t('Configuration updates'), 'Configuration updates found.');
+    $this->assertNoText($this->t('Configuration deletions'), 'No configuration deletions found.');
     $this->assertNoText($entity2->id(), 'Entity2 id not found');
     $this->assertText($entity2->label(), 'Entity2 label not found');
     $this->assertNoText($entity3->id(), 'Entity3 id not found');
diff --git a/core/modules/config/src/Tests/ConfigEntityFormOverrideTest.php b/core/modules/config/src/Tests/ConfigEntityFormOverrideTest.php
index 632d2dc..ff683b5 100644
--- a/core/modules/config/src/Tests/ConfigEntityFormOverrideTest.php
+++ b/core/modules/config/src/Tests/ConfigEntityFormOverrideTest.php
@@ -8,6 +8,7 @@
 namespace Drupal\config\Tests;
 
 use Drupal\simpletest\WebTestBase;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * Tests that config overrides do not bleed through in entity forms and lists.
@@ -15,6 +16,7 @@
  * @group config
  */
 class ConfigEntityFormOverrideTest extends WebTestBase {
+  use StringTranslationTrait;
 
   /**
    * {@inheritdoc}
@@ -58,7 +60,7 @@ public function testFormsWithOverrides() {
     $edit = array(
       'label' => $edited_label,
     );
-    $this->drupalPostForm(NULL, $edit, t('Save'));
+    $this->drupalPostForm(NULL, $edit, $this->t('Save'));
     $this->drupalGet('admin/structure/config_test');
     $this->assertNoText($overridden_label);
     $this->assertText($edited_label);
diff --git a/core/modules/config/src/Tests/ConfigEntityListMultilingualTest.php b/core/modules/config/src/Tests/ConfigEntityListMultilingualTest.php
index 7b0097a..80c3449 100644
--- a/core/modules/config/src/Tests/ConfigEntityListMultilingualTest.php
+++ b/core/modules/config/src/Tests/ConfigEntityListMultilingualTest.php
@@ -9,6 +9,7 @@
 
 use Drupal\simpletest\WebTestBase;
 use Drupal\language\Entity\ConfigurableLanguage;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * Tests the listing of configuration entities in a multilingual scenario.
@@ -16,6 +17,7 @@
  * @group config
  */
 class ConfigEntityListMultilingualTest extends WebTestBase {
+  use StringTranslationTrait;
 
   /**
    * Modules to enable.
@@ -54,7 +56,7 @@ function testListUI() {
       'id' => 'antilop',
       'langcode' => 'hu',
     );
-    $this->drupalPostForm(NULL, $edit, t('Save'));
+    $this->drupalPostForm(NULL, $edit, $this->t('Save'));
     // Ensure that operations for editing the Hungarian entity appear in English.
     $this->assertLinkByHref('admin/structure/config_test/manage/antilop');
 
diff --git a/core/modules/config/src/Tests/ConfigEntityListTest.php b/core/modules/config/src/Tests/ConfigEntityListTest.php
index 9b74a5f..c1a9497 100644
--- a/core/modules/config/src/Tests/ConfigEntityListTest.php
+++ b/core/modules/config/src/Tests/ConfigEntityListTest.php
@@ -10,6 +10,7 @@
 use Drupal\simpletest\WebTestBase;
 use Drupal\config_test\Entity\ConfigTest;
 use Drupal\Core\Entity\EntityStorageInterface;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * Tests the listing of configuration entities.
@@ -17,6 +18,8 @@
  * @group config
  */
 class ConfigEntityListTest extends WebTestBase {
+	
+  use StringTranslationTrait;
 
   /**
    * Modules to enable.
@@ -57,17 +60,17 @@ function testList() {
     // Test getOperations() method.
     $expected_operations = array(
       'edit' => array (
-        'title' => t('Edit'),
+        'title' => $this->t('Edit'),
         'weight' => 10,
         'url' => $entity->urlInfo(),
       ),
       'disable' => array(
-        'title' => t('Disable'),
+        'title' => $this->t('Disable'),
         'weight' => 40,
         'url' => $entity->urlInfo('disable'),
       ),
       'delete' => array (
-        'title' => t('Delete'),
+        'title' => $this->t('Delete'),
         'weight' => 100,
         'url' => $entity->urlInfo('delete-form'),
       ),
@@ -132,12 +135,12 @@ function testList() {
     // Test getOperations() method.
     $expected_operations = array(
       'edit' => array(
-        'title' => t('Edit'),
+        'title' => $this->t('Edit'),
         'weight' => 10,
         'url' => $entity->urlInfo(),
       ),
       'delete' => array(
-        'title' => t('Delete'),
+        'title' => $this->t('Delete'),
         'weight' => 100,
         'url' => $entity->urlInfo('delete-form'),
       ),
@@ -196,7 +199,7 @@ function testListUI() {
       'id' => 'antelope',
       'weight' => 1,
     );
-    $this->drupalPostForm(NULL, $edit, t('Save'));
+    $this->drupalPostForm(NULL, $edit, $this->t('Save'));
 
     // Ensure that the entity's sort method was called.
     $this->assertTrue(\Drupal::state()->get('config_entity_sort'), 'ConfigTest::sort() was called.');
@@ -213,7 +216,7 @@ function testListUI() {
     $this->assertResponse(200);
     $this->assertTitle('Edit Antelope | Drupal');
     $edit = array('label' => 'Albatross', 'id' => 'albatross');
-    $this->drupalPostForm(NULL, $edit, t('Save'));
+    $this->drupalPostForm(NULL, $edit, $this->t('Save'));
 
     // Confirm that the user is returned to the listing, and verify that the
     // text of the label and machine name appears in the list (versus elsewhere
@@ -226,7 +229,7 @@ function testListUI() {
     $this->clickLink('Delete', 1);
     $this->assertResponse(200);
     $this->assertTitle('Are you sure you want to delete the test configuration Albatross? | Drupal');
-    $this->drupalPostForm(NULL, array(), t('Delete'));
+    $this->drupalPostForm(NULL, array(), $this->t('Delete'));
 
     // Verify that the text of the label and machine name does not appear in
     // the list (though it may appear elsewhere on the page).
@@ -237,7 +240,7 @@ function testListUI() {
     $this->clickLink('Delete');
     $this->assertResponse(200);
     $this->assertTitle('Are you sure you want to delete the test configuration Default? | Drupal');
-    $this->drupalPostForm(NULL, array(), t('Delete'));
+    $this->drupalPostForm(NULL, array(), $this->t('Delete'));
 
     // Verify that the text of the label and machine name does not appear in
     // the list (though it may appear elsewhere on the page).
@@ -274,7 +277,7 @@ public function testPager() {
     $this->assertNoRaw('Test config entity 51', 'Config entity 51 is on the next page.');
 
     // Browse to the next page.
-    $this->clickLink(t('Page 2'));
+    $this->clickLink($this->t('Page 2'));
     $this->assertNoRaw('Test config entity 50', 'Test config entity 50 is on the previous page.');
     $this->assertRaw('dotted.default', 'Default config entity appears on page 2.');
     $this->assertRaw('Test config entity 51', 'Test config entity 51 is on page 2.');
diff --git a/core/modules/config/src/Tests/ConfigEntityTest.php b/core/modules/config/src/Tests/ConfigEntityTest.php
index 13ab721..ce62335 100644
--- a/core/modules/config/src/Tests/ConfigEntityTest.php
+++ b/core/modules/config/src/Tests/ConfigEntityTest.php
@@ -14,6 +14,7 @@
 use Drupal\Core\Config\Entity\Exception\ConfigEntityIdLengthException;
 use Drupal\Core\Url;
 use Drupal\simpletest\WebTestBase;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * Tests configuration entities.
@@ -21,6 +22,7 @@
  * @group config
  */
 class ConfigEntityTest extends WebTestBase {
+  use StringTranslationTrait;
 
   /**
    * The maximum length for the entity storage used in this test.
@@ -271,7 +273,7 @@ function testCRUDUI() {
 
     // Delete the configuration entity.
     $this->drupalGet("admin/structure/config_test/manage/$id");
-    $this->clickLink(t('Delete'));
+    $this->clickLink($this->t('Delete'));
     $this->assertUrl("admin/structure/config_test/manage/$id/delete");
     $this->drupalPostForm(NULL, array(), 'Delete');
     $this->assertUrl('admin/structure/config_test');
diff --git a/core/modules/config/src/Tests/ConfigExportImportUITest.php b/core/modules/config/src/Tests/ConfigExportImportUITest.php
index d72c718..e4543a5 100644
--- a/core/modules/config/src/Tests/ConfigExportImportUITest.php
+++ b/core/modules/config/src/Tests/ConfigExportImportUITest.php
@@ -12,6 +12,7 @@
 use Drupal\field\Entity\FieldConfig;
 use Drupal\field\Entity\FieldStorageConfig;
 use Drupal\simpletest\WebTestBase;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * Tests the user interface for importing/exporting configuration.
@@ -23,6 +24,7 @@
  * @group config
  */
 class ConfigExportImportUITest extends WebTestBase {
+  use StringTranslationTrait;
 
   /**
    * The contents of the config export tarball, held between test methods.
@@ -92,8 +94,8 @@ protected function setUp() {
   public function testExportImport() {
     // After installation there is no snapshot and nothing to import.
     $this->drupalGet('admin/config/development/configuration');
-    $this->assertNoText(t('Warning message'));
-    $this->assertText(t('There are no configuration changes to import.'));
+    $this->assertNoText($this->t('Warning message'));
+    $this->assertText($this->t('There are no configuration changes to import.'));
 
     $this->originalSlogan = $this->config('system.site')->get('slogan');
     $this->newSlogan = $this->randomString(16);
@@ -168,14 +170,14 @@ public function testExportImport() {
     file_put_contents($filename, $this->tarball);
     $this->drupalPostForm('admin/config/development/configuration/full/import', array('files[import_tarball]' => $filename), 'Upload');
     // There is no snapshot yet because an import has never run.
-    $this->assertNoText(t('Warning message'));
-    $this->assertNoText(t('There are no configuration changes to import.'));
+    $this->assertNoText($this->t('Warning message'));
+    $this->assertNoText($this->t('There are no configuration changes to import.'));
     $this->assertText($this->contentType->label());
 
     $this->drupalPostForm(NULL, array(), 'Import all');
     // After importing the snapshot has been updated an there are no warnings.
-    $this->assertNoText(t('Warning message'));
-    $this->assertText(t('There are no configuration changes to import.'));
+    $this->assertNoText($this->t('Warning message'));
+    $this->assertText($this->t('There are no configuration changes to import.'));
 
     $this->assertEqual($this->config('system.site')->get('slogan'), $this->newSlogan);
 
@@ -186,7 +188,7 @@ public function testExportImport() {
       ->set('slogan', $this->originalSlogan)
       ->save();
     $this->drupalGet('admin/config/development/configuration');
-    $this->assertText(t('Warning message'));
+    $this->assertText($this->t('Warning message'));
     $this->assertText('The following items in your active configuration have changes since the last import that may be lost on the next import.');
     // Ensure the item is displayed as part of a list (to avoid false matches
     // on the rest of the page) and that the list markup is not escaped.
@@ -195,9 +197,9 @@ public function testExportImport() {
     // active and snapshot should no longer exist.
     \Drupal::service('config.storage.sync')->deleteAll();
     $this->drupalGet('admin/config/development/configuration');
-    $this->assertNoText(t('Warning message'));
+    $this->assertNoText($this->t('Warning message'));
     $this->assertNoText('The following items in your active configuration have changes since the last import that may be lost on the next import.');
-    $this->assertText(t('There are no configuration changes to import.'));
+    $this->assertText($this->t('There are no configuration changes to import.'));
     // Write a file to sync. The warning about differences between the active
     // and snapshot should now exist.
     /** @var \Drupal\Core\Config\StorageInterface $sync */
@@ -207,7 +209,7 @@ public function testExportImport() {
     $this->copyConfig($this->container->get('config.storage'), $sync);
     $sync->write('system.site', $data);
     $this->drupalGet('admin/config/development/configuration');
-    $this->assertText(t('Warning message'));
+    $this->assertText($this->t('Warning message'));
     $this->assertText('The following items in your active configuration have changes since the last import that may be lost on the next import.');
     // Ensure the item is displayed as part of a list (to avoid false matches
     // on the rest of the page) and that the list markup is not escaped.
@@ -278,9 +280,9 @@ public function testExportImportCollections() {
     $this->drupalPostForm('admin/config/development/configuration/full/import', array('files[import_tarball]' => $filename), 'Upload');
     // Verify that there are configuration differences to import.
     $this->drupalGet('admin/config/development/configuration');
-    $this->assertNoText(t('There are no configuration changes to import.'));
-    $this->assertText(t('@collection configuration collection', array('@collection' => 'collection.test1')));
-    $this->assertText(t('@collection configuration collection', array('@collection' => 'collection.test2')));
+    $this->assertNoText($this->t('There are no configuration changes to import.'));
+    $this->assertText($this->t('@collection configuration collection', array('@collection' => 'collection.test1')));
+    $this->assertText($this->t('@collection configuration collection', array('@collection' => 'collection.test2')));
     $this->assertText('config_test.create');
     $this->assertLinkByHref('admin/config/development/configuration/sync/diff_collection/collection.test1/config_test.create');
     $this->assertText('config_test.update');
@@ -295,7 +297,7 @@ public function testExportImportCollections() {
     $this->assertLinkByHref('admin/config/development/configuration/sync/diff_collection/collection.test2/config_test.another_delete');
 
     $this->drupalPostForm(NULL, array(), 'Import all');
-    $this->assertText(t('There are no configuration changes to import.'));
+    $this->assertText($this->t('There are no configuration changes to import.'));
 
     // Test data in collections.
     $data = $test1_storage->read('config_test.create');
diff --git a/core/modules/config/src/Tests/ConfigExportUITest.php b/core/modules/config/src/Tests/ConfigExportUITest.php
index e6329c6..a9197d6 100644
--- a/core/modules/config/src/Tests/ConfigExportUITest.php
+++ b/core/modules/config/src/Tests/ConfigExportUITest.php
@@ -10,6 +10,7 @@
 use Drupal\Component\Serialization\Yaml;
 use Drupal\Core\Archiver\Tar;
 use Drupal\simpletest\WebTestBase;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * Tests the user interface for exporting configuration.
@@ -17,6 +18,7 @@
  * @group config
  */
 class ConfigExportUITest extends WebTestBase {
+  use StringTranslationTrait;
 
   /**
    * Modules to enable.
@@ -47,10 +49,10 @@ protected function setUp() {
   function testExport() {
     // Verify the export page with export submit button is available.
     $this->drupalGet('admin/config/development/configuration/full/export');
-    $this->assertFieldById('edit-submit', t('Export'));
+    $this->assertFieldById('edit-submit', $this->t('Export'));
 
     // Submit the export form and verify response.
-    $this->drupalPostForm('admin/config/development/configuration/full/export', array(), t('Export'));
+    $this->drupalPostForm('admin/config/development/configuration/full/export', array(), $this->t('Export'));
     $this->assertResponse(200, 'User can access the download callback.');
 
     // Test if header contains file name with hostname and timestamp.
diff --git a/core/modules/config/src/Tests/ConfigFormOverrideTest.php b/core/modules/config/src/Tests/ConfigFormOverrideTest.php
index 14726c5..b657405 100644
--- a/core/modules/config/src/Tests/ConfigFormOverrideTest.php
+++ b/core/modules/config/src/Tests/ConfigFormOverrideTest.php
@@ -8,6 +8,8 @@
 namespace Drupal\config\Tests;
 
 use Drupal\simpletest\WebTestBase;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
+
 
 /**
  * Tests config overrides do not appear on forms that extend ConfigFormBase.
@@ -16,6 +18,7 @@
  * @see \Drupal\Core\Form\ConfigFormBase
  */
 class ConfigFormOverrideTest extends WebTestBase {
+  use StringTranslationTrait;
 
   /**
    * Tests that overrides do not affect forms.
@@ -43,7 +46,7 @@ public function testFormsWithOverrides() {
     $edit = array(
       'site_name' => 'Custom site name',
     );
-    $this->drupalPostForm('admin/config/system/site-information', $edit, t('Save configuration'));
+    $this->drupalPostForm('admin/config/system/site-information', $edit, $this->t('Save configuration'));
     $this->assertTitle('Site information | ' . $overridden_name);
     $elements = $this->xpath('//input[@name="site_name"]');
     $this->assertIdentical((string) $elements[0]['value'], $edit['site_name']);
diff --git a/core/modules/config/src/Tests/ConfigImportAllTest.php b/core/modules/config/src/Tests/ConfigImportAllTest.php
index d496973..673486b 100644
--- a/core/modules/config/src/Tests/ConfigImportAllTest.php
+++ b/core/modules/config/src/Tests/ConfigImportAllTest.php
@@ -12,6 +12,7 @@
 use Drupal\system\Tests\Module\ModuleTestBase;
 use Drupal\shortcut\Entity\Shortcut;
 use Drupal\taxonomy\Entity\Term;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * Tests the largest configuration import possible with all available modules.
@@ -21,6 +22,7 @@
 class ConfigImportAllTest extends ModuleTestBase {
 
   use SchemaCheckTestTrait;
+  use StringTranslationTrait;
 
   /**
    * A user with the 'synchronize configuration' permission.
@@ -129,7 +131,7 @@ public function testInstallUninstall() {
     }
 
     // Import the configuration thereby re-installing all the modules.
-    $this->drupalPostForm('admin/config/development/configuration', array(), t('Import all'));
+    $this->drupalPostForm('admin/config/development/configuration', array(), $this->t('Import all'));
     // Modules have been installed that have services.
     $this->rebuildContainer();
 
diff --git a/core/modules/config/src/Tests/ConfigImportInstallProfileTest.php b/core/modules/config/src/Tests/ConfigImportInstallProfileTest.php
index e15d3ac..5c2e055 100644
--- a/core/modules/config/src/Tests/ConfigImportInstallProfileTest.php
+++ b/core/modules/config/src/Tests/ConfigImportInstallProfileTest.php
@@ -8,6 +8,7 @@
 namespace Drupal\config\Tests;
 
 use Drupal\simpletest\WebTestBase;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * Tests the importing/exporting configuration based on the install profile.
@@ -15,7 +16,7 @@
  * @group config
  */
 class ConfigImportInstallProfileTest extends WebTestBase {
-
+  use StringTranslationTrait;
   /**
    * The profile to install as a basis for testing.
    *
@@ -59,7 +60,7 @@ public function testInstallProfileValidation() {
     unset($core['module']['testing_config_import']);
     $sync->write('core.extension', $core);
 
-    $this->drupalPostForm('admin/config/development/configuration', array(), t('Import all'));
+    $this->drupalPostForm('admin/config/development/configuration', array(), $this->t('Import all'));
     $this->assertText('The configuration cannot be imported because it failed validation for the following reasons:');
     $this->assertText('Unable to uninstall the Testing config import profile since it is the install profile.');
 
@@ -74,7 +75,7 @@ public function testInstallProfileValidation() {
     $theme = $sync->read('system.theme');
     $theme['default'] = 'classy';
     $sync->write('system.theme', $theme);
-    $this->drupalPostForm('admin/config/development/configuration', array(), t('Import all'));
+    $this->drupalPostForm('admin/config/development/configuration', array(), $this->t('Import all'));
     $this->assertText('The configuration was imported successfully.');
     $this->rebuildContainer();
     $this->assertFalse(\Drupal::moduleHandler()->moduleExists('syslog'), 'The syslog module has been uninstalled.');
diff --git a/core/modules/config/src/Tests/ConfigImportUITest.php b/core/modules/config/src/Tests/ConfigImportUITest.php
index 98f11c2..e92ea0b 100644
--- a/core/modules/config/src/Tests/ConfigImportUITest.php
+++ b/core/modules/config/src/Tests/ConfigImportUITest.php
@@ -11,6 +11,7 @@
 use Drupal\Component\Utility\SafeMarkup;
 use Drupal\Core\Config\InstallStorage;
 use Drupal\simpletest\WebTestBase;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * Tests the user interface for importing/exporting configuration.
@@ -18,6 +19,7 @@
  * @group config
  */
 class ConfigImportUITest extends WebTestBase {
+  use StringTranslationTrait;
 
   /**
    * Modules to install.
@@ -52,7 +54,7 @@ function testImport() {
 
     $this->drupalGet('admin/config/development/configuration');
     $this->assertText('There are no configuration changes to import.');
-    $this->assertNoFieldById('edit-submit', t('Import all'));
+    $this->assertNoFieldById('edit-submit', $this->t('Import all'));
 
     // Create updated configuration object.
     $new_site_name = 'Config import test ' . $this->randomString();
@@ -120,17 +122,17 @@ function testImport() {
     $this->assertRaw('<td>core.extension');
     $this->assertRaw('<td>system.theme');
     $this->assertRaw('<td>action.settings');
-    $this->assertFieldById('edit-submit', t('Import all'));
+    $this->assertFieldById('edit-submit', $this->t('Import all'));
 
     // Import and verify that both do not appear anymore.
-    $this->drupalPostForm(NULL, array(), t('Import all'));
+    $this->drupalPostForm(NULL, array(), $this->t('Import all'));
     $this->assertNoRaw('<td>' . $name);
     $this->assertNoRaw('<td>' . $dynamic_name);
     $this->assertNoRaw('<td>core.extension');
     $this->assertNoRaw('<td>system.theme');
     $this->assertNoRaw('<td>action.settings');
 
-    $this->assertNoFieldById('edit-submit', t('Import all'));
+    $this->assertNoFieldById('edit-submit', $this->t('Import all'));
 
     // Verify that there are no further changes to import.
     $this->assertText(t('There are no configuration changes to import.'));
@@ -195,7 +197,7 @@ function testImport() {
     $this->assertRaw('<td>action.settings');
 
     // Import and verify that both do not appear anymore.
-    $this->drupalPostForm(NULL, array(), t('Import all'));
+    $this->drupalPostForm(NULL, array(), $this->t('Import all'));
     $this->assertNoRaw('<td>core.extension');
     $this->assertNoRaw('<td>system.theme');
     $this->assertNoRaw('<td>action.settings');
@@ -240,7 +242,7 @@ function testImportLock() {
     $this->container->get('lock.persistent')->acquire($config_importer::LOCK_NAME);
 
     // Attempt to import configuration and verify that an error message appears.
-    $this->drupalPostForm(NULL, array(), t('Import all'));
+    $this->drupalPostForm(NULL, array(), $this->t('Import all'));
     $this->assertText(t('Another request may be synchronizing configuration already.'));
 
     // Release the lock, just to keep testing sane.
@@ -264,7 +266,7 @@ function testImportSiteUuidValidation() {
     // Verify that there are configuration differences to import.
     $this->drupalGet('admin/config/development/configuration');
     $this->assertText(t('The staged configuration cannot be imported, because it originates from a different site than this site. You can only synchronize configuration between cloned instances of this site.'));
-    $this->assertNoFieldById('edit-submit', t('Import all'));
+    $this->assertNoFieldById('edit-submit', $this->t('Import all'));
   }
 
   /**
@@ -356,7 +358,7 @@ public function testImportValidation() {
 
     $this->drupalGet('admin/config/development/configuration');
     $this->assertNoText(t('There are no configuration changes to import.'));
-    $this->drupalPostForm(NULL, array(), t('Import all'));
+    $this->drupalPostForm(NULL, array(), $this->t('Import all'));
 
     // Verify that the validation messages appear.
     $this->assertText('The configuration cannot be imported because it failed validation for the following reasons:');
@@ -378,7 +380,7 @@ public function testConfigUninstallConfigException() {
     $this->assertText('core.extension');
 
     // Import and verify that both do not appear anymore.
-    $this->drupalPostForm(NULL, array(), t('Import all'));
+    $this->drupalPostForm(NULL, array(), $this->t('Import all'));
     $this->assertText('Can not uninstall the Configuration module as part of a configuration synchronization through the user interface.');
   }
 
@@ -435,7 +437,7 @@ function testImportErrorLog() {
     $this->assertNoText(t('There are no configuration changes to import.'));
 
     // Attempt to import configuration and verify that an error message appears.
-    $this->drupalPostForm(NULL, array(), t('Import all'));
+    $this->drupalPostForm(NULL, array(), $this->t('Import all'));
     $this->assertText(SafeMarkup::format('Deleted and replaced configuration entity "@name"', array('@name' => $name_secondary)));
     $this->assertText(t('The configuration was imported with errors.'));
     $this->assertNoText(t('The configuration was imported successfully.'));
@@ -465,8 +467,8 @@ public function testEntityBundleDelete() {
     // Attempt to import configuration and verify that an error message appears
     // and the node type, body field and entity displays are still scheduled for
     // removal.
-    $this->drupalPostForm(NULL, array(), t('Import all'));
-    $validation_message = t('Entities exist of type %entity_type and %bundle_label %bundle. These entities need to be deleted before importing.', array('%entity_type' => $node->getEntityType()->getLabel(), '%bundle_label' => $node->getEntityType()->getBundleLabel(), '%bundle' => $node_type->label()));
+    $this->drupalPostForm(NULL, array(), $this->t('Import all'));
+    $validation_message = $this->t('Entities exist of type %entity_type and %bundle_label %bundle. These entities need to be deleted before importing.', array('%entity_type' => $node->getEntityType()->getLabel(), '%bundle_label' => $node->getEntityType()->getBundleLabel(), '%bundle' => $node_type->label()));
     $this->assertRaw($validation_message);
     $this->assertText(format_string('node.type.@type', array('@type' => $node_type->id())));
     $this->assertText(format_string('field.field.node.@type.body', array('@type' => $node_type->id())));
@@ -476,9 +478,9 @@ public function testEntityBundleDelete() {
 
     // Delete the node and try to import again.
     $node->delete();
-    $this->drupalPostForm(NULL, array(), t('Import all'));
+    $this->drupalPostForm(NULL, array(), $this->t('Import all'));
     $this->assertNoRaw($validation_message);
-    $this->assertText(t('There are no configuration changes to import.'));
+    $this->assertText($this->t('There are no configuration changes to import.'));
     $this->assertNoText(format_string('node.type.@type', array('@type' => $node_type->id())));
     $this->assertNoText(format_string('field.field.node.@type.body', array('@type' => $node_type->id())));
     $this->assertNoText(format_string('core.entity_view_display.node.@type.teaser', array('@type' => $node_type->id())));
@@ -513,7 +515,7 @@ public function testExtensionValidation() {
     $core['theme']['does_not_exist'] = 0;
     $sync->write('core.extension', $core);
 
-    $this->drupalPostForm('admin/config/development/configuration', array(), t('Import all'));
+    $this->drupalPostForm('admin/config/development/configuration', array(), $this->t('Import all'));
     $this->assertText('The configuration cannot be imported because it failed validation for the following reasons:');
     $this->assertText('Unable to uninstall the Text module since the Node module is installed.');
     $this->assertText('Unable to uninstall the Classy theme since the Bartik theme is installed.');
diff --git a/core/modules/config/src/Tests/ConfigImportUploadTest.php b/core/modules/config/src/Tests/ConfigImportUploadTest.php
index 33f6171..914656d 100644
--- a/core/modules/config/src/Tests/ConfigImportUploadTest.php
+++ b/core/modules/config/src/Tests/ConfigImportUploadTest.php
@@ -8,6 +8,7 @@
 namespace Drupal\config\Tests;
 
 use Drupal\simpletest\WebTestBase;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * Tests importing configuration from an uploaded file.
@@ -15,6 +16,7 @@
  * @group config
  */
 class ConfigImportUploadTest extends WebTestBase {
+  use StringTranslationTrait;
 
   /**
    * A user with the 'import configuration' permission.
@@ -48,8 +50,8 @@ function testImport() {
     // Attempt to upload a non-tar file.
     $text_file = current($this->drupalGetTestFiles('text'));
     $edit = array('files[import_tarball]' => drupal_realpath($text_file->uri));
-    $this->drupalPostForm('admin/config/development/configuration/full/import', $edit, t('Upload'));
-    $this->assertText(t('Could not extract the contents of the tar file'));
+    $this->drupalPostForm('admin/config/development/configuration/full/import', $edit, $this->t('Upload'));
+    $this->assertText($this->t('Could not extract the contents of the tar file'));
   }
 
 }
diff --git a/core/modules/config/src/Tests/ConfigInstallWebTest.php b/core/modules/config/src/Tests/ConfigInstallWebTest.php
index 221d09f..b1ced1e 100644
--- a/core/modules/config/src/Tests/ConfigInstallWebTest.php
+++ b/core/modules/config/src/Tests/ConfigInstallWebTest.php
@@ -11,6 +11,7 @@
 use Drupal\Core\Config\StorageInterface;
 use Drupal\language\Entity\ConfigurableLanguage;
 use Drupal\simpletest\WebTestBase;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * Tests installation and removal of configuration objects in install, disable
@@ -19,6 +20,7 @@
  * @group config
  */
 class ConfigInstallWebTest extends WebTestBase {
+  use StringTranslationTrait;
 
   /**
    * The admin user used in this test.
@@ -127,19 +129,19 @@ public function testPreExistingConfigInstall() {
     // will install the config_test module first because it is a dependency of
     // config_install_fail_test.
     // @see \Drupal\system\Form\ModulesListForm::submitForm()
-    $this->drupalPostForm('admin/modules', array('modules[Testing][config_test][enable]' => TRUE, 'modules[Testing][config_install_fail_test][enable]' => TRUE), t('Install'));
+    $this->drupalPostForm('admin/modules', array('modules[Testing][config_test][enable]' => TRUE, 'modules[Testing][config_install_fail_test][enable]' => TRUE), $this->t('Install'));
     $this->assertRaw('Unable to install Configuration install fail test, <em class="placeholder">config_test.dynamic.dotted.default</em> already exists in active configuration.');
 
     // Uninstall the config_test module to test the confirm form.
-    $this->drupalPostForm('admin/modules/uninstall', array('uninstall[config_test]' => TRUE), t('Uninstall'));
-    $this->drupalPostForm(NULL, array(), t('Uninstall'));
+    $this->drupalPostForm('admin/modules/uninstall', array('uninstall[config_test]' => TRUE), $this->t('Uninstall'));
+    $this->drupalPostForm(NULL, array(), $this->t('Uninstall'));
 
     // Try to install config_install_fail_test without selecting config_test.
     // The user is shown a confirm form because the config_test module is a
     // dependency.
     // @see \Drupal\system\Form\ModulesListConfirmForm::submitForm()
-    $this->drupalPostForm('admin/modules', array('modules[Testing][config_install_fail_test][enable]' => TRUE), t('Install'));
-    $this->drupalPostForm(NULL, array(), t('Continue'));
+    $this->drupalPostForm('admin/modules', array('modules[Testing][config_install_fail_test][enable]' => TRUE), $this->t('Install'));
+    $this->drupalPostForm(NULL, array(), $this->t('Continue'));
     $this->assertRaw('Unable to install Configuration install fail test, <em class="placeholder">config_test.dynamic.dotted.default</em> already exists in active configuration.');
 
     // Test that collection configuration clashes during a module install are
@@ -152,7 +154,7 @@ public function testPreExistingConfigInstall() {
       ->set('label', 'Je suis Charlie')
       ->save();
 
-    $this->drupalPostForm('admin/modules', array('modules[Testing][config_install_fail_test][enable]' => TRUE), t('Install'));
+    $this->drupalPostForm('admin/modules', array('modules[Testing][config_install_fail_test][enable]' => TRUE), $this->t('Install'));
     $this->assertRaw('Unable to install Configuration install fail test, <em class="placeholder">config_test.dynamic.dotted.default, language/fr/config_test.dynamic.dotted.default</em> already exist in active configuration.');
 
     // Test installing a theme through the UI that has existing configuration.
@@ -183,12 +185,12 @@ public function testUnmetDependenciesInstall() {
     $this->drupalLogin($this->adminUser);
     // We need to install separately since config_install_dependency_test does
     // not depend on config_test and order is important.
-    $this->drupalPostForm('admin/modules', array('modules[Testing][config_test][enable]' => TRUE), t('Install'));
-    $this->drupalPostForm('admin/modules', array('modules[Testing][config_install_dependency_test][enable]' => TRUE), t('Install'));
+    $this->drupalPostForm('admin/modules', array('modules[Testing][config_test][enable]' => TRUE), $this->t('Install'));
+    $this->drupalPostForm('admin/modules', array('modules[Testing][config_install_dependency_test][enable]' => TRUE), $this->t('Install'));
     $this->assertRaw('Unable to install Config install dependency test, <em class="placeholder">config_test.dynamic.other_module_test_with_dependency</em> has unmet dependencies.');
 
-    $this->drupalPostForm('admin/modules', array('modules[Testing][config_other_module_config_test][enable]' => TRUE), t('Install'));
-    $this->drupalPostForm('admin/modules', array('modules[Testing][config_install_dependency_test][enable]' => TRUE), t('Install'));
+    $this->drupalPostForm('admin/modules', array('modules[Testing][config_other_module_config_test][enable]' => TRUE), $this->t('Install'));
+    $this->drupalPostForm('admin/modules', array('modules[Testing][config_install_dependency_test][enable]' => TRUE), $this->t('Install'));
     $this->rebuildContainer();
     $this->assertTrue(entity_load('config_test', 'other_module_test_with_dependency'), 'The config_test.dynamic.other_module_test_with_dependency configuration has been created during install.');
   }
diff --git a/core/modules/config/src/Tests/ConfigLanguageOverrideWebTest.php b/core/modules/config/src/Tests/ConfigLanguageOverrideWebTest.php
index 79ed24c..a2d8d93 100644
--- a/core/modules/config/src/Tests/ConfigLanguageOverrideWebTest.php
+++ b/core/modules/config/src/Tests/ConfigLanguageOverrideWebTest.php
@@ -10,6 +10,7 @@
 use Drupal\Core\Language\LanguageInterface;
 use Drupal\language\Entity\ConfigurableLanguage;
 use Drupal\simpletest\WebTestBase;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * Tests language overrides applied through the website.
@@ -17,6 +18,7 @@
  * @group config
  */
 class ConfigLanguageOverrideWebTest extends WebTestBase {
+  use StringTranslationTrait;
 
   /**
    * Modules to install.
@@ -52,7 +54,7 @@ function testSiteNameTranslation() {
       'label' => $name,
       'direction' => LanguageInterface::DIRECTION_LTR,
     );
-    $this->drupalPostForm('admin/config/regional/language/add', $edit, t('Add custom language'));
+    $this->drupalPostForm('admin/config/regional/language/add', $edit, $this->t('Add custom language'));
     \Drupal::languageManager()
       ->getLanguageConfigOverride($langcode, 'system.site')
       ->set('name', 'XX site name')
diff --git a/core/modules/config/src/Tests/ConfigSingleImportExportTest.php b/core/modules/config/src/Tests/ConfigSingleImportExportTest.php
index 088129a..154016f 100644
--- a/core/modules/config/src/Tests/ConfigSingleImportExportTest.php
+++ b/core/modules/config/src/Tests/ConfigSingleImportExportTest.php
@@ -9,6 +9,7 @@
 
 use Drupal\Component\Serialization\Yaml;
 use Drupal\simpletest\WebTestBase;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * Tests the user interface for importing/exporting a single configuration.
@@ -16,6 +17,7 @@
  * @group config
  */
 class ConfigSingleImportExportTest extends WebTestBase {
+  use StringTranslationTrait;
 
   /**
    * Modules to enable.
@@ -53,15 +55,15 @@ public function testImport() {
       'import' => $import,
     );
     // Attempt an import with a missing ID.
-    $this->drupalPostForm('admin/config/development/configuration/single/import', $edit, t('Import'));
+    $this->drupalPostForm('admin/config/development/configuration/single/import', $edit, $this->t('Import'));
     $this->assertText(t('Missing ID key "@id_key" for this @entity_type import.', array('@id_key' => 'id', '@entity_type' => 'Test configuration')));
 
     // Perform an import with no specified UUID and a unique ID.
     $this->assertNull($storage->load('first'));
     $edit['import'] = "id: first\n" . $edit['import'];
-    $this->drupalPostForm('admin/config/development/configuration/single/import', $edit, t('Import'));
+    $this->drupalPostForm('admin/config/development/configuration/single/import', $edit, $this->t('Import'));
     $this->assertRaw(t('Are you sure you want to create a new %name @type?', array('%name' => 'first', '@type' => 'test configuration')));
-    $this->drupalPostForm(NULL, array(), t('Confirm'));
+    $this->drupalPostForm(NULL, array(), $this->t('Confirm'));
     $entity = $storage->load('first');
     $this->assertIdentical($entity->label(), 'First');
     $this->assertIdentical($entity->id(), 'first');
@@ -69,19 +71,19 @@ public function testImport() {
     $this->assertRaw(t('The configuration was imported successfully.'));
 
     // Attempt an import with an existing ID but missing UUID.
-    $this->drupalPostForm('admin/config/development/configuration/single/import', $edit, t('Import'));
+    $this->drupalPostForm('admin/config/development/configuration/single/import', $edit, $this->t('Import'));
     $this->assertText(t('An entity with this machine name already exists but the import did not specify a UUID.'));
 
     // Attempt an import with a mismatched UUID and existing ID.
     $edit['import'] .= "\nuuid: " . $uuid->generate();
-    $this->drupalPostForm('admin/config/development/configuration/single/import', $edit, t('Import'));
+    $this->drupalPostForm('admin/config/development/configuration/single/import', $edit, $this->t('Import'));
     $this->assertText(t('An entity with this machine name already exists but the UUID does not match.'));
 
     // Attempt an import with a custom ID.
     $edit['custom_entity_id'] = 'custom_id';
-    $this->drupalPostForm('admin/config/development/configuration/single/import', $edit, t('Import'));
+    $this->drupalPostForm('admin/config/development/configuration/single/import', $edit, $this->t('Import'));
     $this->assertRaw(t('Are you sure you want to create a new %name @type?', array('%name' => 'custom_id', '@type' => 'test configuration')));
-    $this->drupalPostForm(NULL, array(), t('Confirm'));
+    $this->drupalPostForm(NULL, array(), $this->t('Confirm'));
     $this->assertRaw(t('The configuration was imported successfully.'));
 
     // Perform an import with a unique ID and UUID.
@@ -98,9 +100,9 @@ public function testImport() {
     );
     $second_uuid = $uuid->generate();
     $edit['import'] .= "\nuuid: " . $second_uuid;
-    $this->drupalPostForm('admin/config/development/configuration/single/import', $edit, t('Import'));
+    $this->drupalPostForm('admin/config/development/configuration/single/import', $edit, $this->t('Import'));
     $this->assertRaw(t('Are you sure you want to create a new %name @type?', array('%name' => 'second', '@type' => 'test configuration')));
-    $this->drupalPostForm(NULL, array(), t('Confirm'));
+    $this->drupalPostForm(NULL, array(), $this->t('Confirm'));
     $entity = $storage->load('second');
     $this->assertRaw(t('The configuration was imported successfully.'));
     $this->assertIdentical($entity->label(), 'Second');
@@ -121,9 +123,9 @@ public function testImport() {
       'config_type' => 'config_test',
       'import' => $import,
     );
-    $this->drupalPostForm('admin/config/development/configuration/single/import', $edit, t('Import'));
+    $this->drupalPostForm('admin/config/development/configuration/single/import', $edit, $this->t('Import'));
     $this->assertRaw(t('Are you sure you want to update the %name @type?', array('%name' => 'second', '@type' => 'test configuration')));
-    $this->drupalPostForm(NULL, array(), t('Confirm'));
+    $this->drupalPostForm(NULL, array(), $this->t('Confirm'));
     $entity = $storage->load('second');
     $this->assertRaw(t('The configuration was imported successfully.'));
     $this->assertIdentical($entity->label(), 'Second updated');
@@ -144,7 +146,7 @@ public function testImport() {
       'config_type' => 'config_test',
       'import' => $import,
     );
-    $this->drupalPostForm('admin/config/development/configuration/single/import', $edit, t('Import'));
+    $this->drupalPostForm('admin/config/development/configuration/single/import', $edit, $this->t('Import'));
     $this->assertRaw(t('Configuration %name depends on the %owner module that will not be installed after import.', ['%name' => 'config_test.dynamic.second', '%owner' => 'does_not_exist']));
   }
 
@@ -163,9 +165,9 @@ public function testImportSimpleConfiguration() {
       'config_name' => $config->getName(),
       'import' => Yaml::encode($config->get()),
     );
-    $this->drupalPostForm('admin/config/development/configuration/single/import', $edit, t('Import'));
+    $this->drupalPostForm('admin/config/development/configuration/single/import', $edit, $this->t('Import'));
     $this->assertRaw(t('Are you sure you want to update the %name @type?', array('%name' => $config->getName(), '@type' => 'simple configuration')));
-    $this->drupalPostForm(NULL, array(), t('Confirm'));
+    $this->drupalPostForm(NULL, array(), $this->t('Confirm'));
     $this->drupalGet('');
     $this->assertText('Test simple import');
 
@@ -179,7 +181,7 @@ public function testImportSimpleConfiguration() {
       'config_name' => 'core.extension',
       'import' => Yaml::encode($config_data),
     );
-    $this->drupalPostForm('admin/config/development/configuration/single/import', $edit, t('Import'));
+    $this->drupalPostForm('admin/config/development/configuration/single/import', $edit, $this->t('Import'));
     $this->assertText(t('Can not uninstall the Configuration module as part of a configuration synchronization through the user interface.'));
 
   }
@@ -191,7 +193,7 @@ public function testExport() {
     $this->drupalLogin($this->drupalCreateUser(array('export configuration')));
 
     $this->drupalGet('admin/config/development/configuration/single/export/system.simple');
-    $this->assertFieldByXPath('//select[@name="config_type"]//option[@selected="selected"]', t('Simple configuration'), 'The simple configuration option is selected when specified in the URL.');
+    $this->assertFieldByXPath('//select[@name="config_type"]//option[@selected="selected"]', $this->t('Simple configuration'), 'The simple configuration option is selected when specified in the URL.');
     // Spot check several known simple configuration files.
     $element = $this->xpath('//select[@name="config_name"]');
     $options = $this->getAllOptions($element[0]);
@@ -205,10 +207,10 @@ public function testExport() {
     $this->assertFieldByXPath('//textarea[@name="export"]', "toolkit: gd\n_core:\n  default_config_hash: durWHaKeBaq4d9Wpi4RqwADj1OufDepcnJuhVLmKN24\n", 'The expected system configuration is displayed.');
 
     $this->drupalGet('admin/config/development/configuration/single/export/date_format');
-    $this->assertFieldByXPath('//select[@name="config_type"]//option[@selected="selected"]', t('Date format'), 'The date format entity type is selected when specified in the URL.');
+    $this->assertFieldByXPath('//select[@name="config_type"]//option[@selected="selected"]', $this->t('Date format'), 'The date format entity type is selected when specified in the URL.');
 
     $this->drupalGet('admin/config/development/configuration/single/export/date_format/fallback');
-    $this->assertFieldByXPath('//select[@name="config_name"]//option[@selected="selected"]', t('Fallback date format (fallback)'), 'The fallback date format config entity is selected when specified in the URL.');
+    $this->assertFieldByXPath('//select[@name="config_name"]//option[@selected="selected"]', $this->t('Fallback date format (fallback)'), 'The fallback date format config entity is selected when specified in the URL.');
 
     $fallback_date = \Drupal::entityManager()->getStorage('date_format')->load('fallback');
     $data = Yaml::encode($fallback_date->toArray());
diff --git a/core/modules/config/src/Tests/LanguageNegotiationFormOverrideTest.php b/core/modules/config/src/Tests/LanguageNegotiationFormOverrideTest.php
index add0c28..76bd269 100644
--- a/core/modules/config/src/Tests/LanguageNegotiationFormOverrideTest.php
+++ b/core/modules/config/src/Tests/LanguageNegotiationFormOverrideTest.php
@@ -8,6 +8,7 @@
 namespace Drupal\config\Tests;
 
 use Drupal\simpletest\WebTestBase;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * Tests language-negotiation overrides are not on language-negotiation form.
@@ -16,6 +17,7 @@
  * @see \Drupal\Core\Form\ConfigFormBase
  */
 class LanguageNegotiationFormOverrideTest extends WebTestBase {
+  use StringTranslationTrait;
 
   public static $modules = array('language', 'locale', 'locale_test');
 
@@ -38,7 +40,7 @@ public function testFormWithOverride() {
     $edit = array(
       'predefined_langcode' => 'es',
     );
-    $this->drupalPostForm('admin/config/regional/language/add', $edit, t('Add language'));
+    $this->drupalPostForm('admin/config/regional/language/add', $edit, $this->t('Add language'));
 
     // Overridden string for language-negotiation should not exist in the form.
     $this->drupalGet('admin/config/regional/language/detection/url');
diff --git a/core/modules/config/tests/config_override_integration_test/src/Cache/ConfigOverrideIntegrationTestCacheContext.php b/core/modules/config/tests/config_override_integration_test/src/Cache/ConfigOverrideIntegrationTestCacheContext.php
index f2192aa..8c88f3a 100644
--- a/core/modules/config/tests/config_override_integration_test/src/Cache/ConfigOverrideIntegrationTestCacheContext.php
+++ b/core/modules/config/tests/config_override_integration_test/src/Cache/ConfigOverrideIntegrationTestCacheContext.php
@@ -9,6 +9,7 @@
 
 use Drupal\Core\Cache\CacheableMetadata;
 use Drupal\Core\Cache\Context\CacheContextInterface;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * A cache context service intended for the config override integration test.
@@ -16,12 +17,12 @@
  * Cache context ID: 'config_override_integration_test'.
  */
 class ConfigOverrideIntegrationTestCacheContext implements CacheContextInterface {
-
+  use StringTranslationTrait;
   /**
    * {@inheritdoc}
    */
   public static function getLabel() {
-    return t('Config override integration test');
+    return $this->t('Config override integration test');
   }
 
   /**
diff --git a/core/modules/config/tests/config_override_test/src/Cache/PirateDayCacheContext.php b/core/modules/config/tests/config_override_test/src/Cache/PirateDayCacheContext.php
index c40cc6a..a3f62e2 100644
--- a/core/modules/config/tests/config_override_test/src/Cache/PirateDayCacheContext.php
+++ b/core/modules/config/tests/config_override_test/src/Cache/PirateDayCacheContext.php
@@ -9,6 +9,7 @@
 
 use Drupal\Core\Cache\CacheableMetadata;
 use Drupal\Core\Cache\Context\CacheContextInterface;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * Defines the PirateDayCacheContext service that allows to cache the booty.
@@ -16,7 +17,7 @@
  * Cache context ID: 'pirate_day'.
  */
 class PirateDayCacheContext implements CacheContextInterface {
-
+  use StringTranslationTrait;
   /**
    * The length of Pirate Day. It lasts 24 hours.
    *
@@ -32,7 +33,7 @@ class PirateDayCacheContext implements CacheContextInterface {
    * {@inheritdoc}
    */
   public static function getLabel() {
-    return t('Pirate day');
+    return $this->t('Pirate day');
   }
 
   /**
diff --git a/core/modules/config/tests/config_test/src/ConfigTestForm.php b/core/modules/config/tests/config_test/src/ConfigTestForm.php
index 14f4bef..9f97195 100644
--- a/core/modules/config/tests/config_test/src/ConfigTestForm.php
+++ b/core/modules/config/tests/config_test/src/ConfigTestForm.php
@@ -12,12 +12,13 @@
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Language\LanguageInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * Form controller for the test config edit forms.
  */
 class ConfigTestForm extends EntityForm {
-
+  use StringTranslationTrait;
   /**
    * The entity query.
    *
@@ -109,7 +110,7 @@ public function form(array $form, FormStateInterface $form_state) {
     );
     $form['size_wrapper']['size_submit'] = array(
       '#type' => 'submit',
-      '#value' => t('Change size'),
+      '#value' => $this->t('Change size'),
       '#attributes' => array(
         'class' => array('js-hide'),
       ),
@@ -129,7 +130,7 @@ public function form(array $form, FormStateInterface $form_state) {
 
     $form['langcode'] = array(
       '#type' => 'language_select',
-      '#title' => t('Language'),
+      '#title' => $this->t('Language'),
       '#languages' => LanguageInterface::STATE_ALL,
       '#default_value' => $entity->language()->getId(),
     );
diff --git a/core/modules/config/tests/config_test/src/ConfigTestListBuilder.php b/core/modules/config/tests/config_test/src/ConfigTestListBuilder.php
index 4680ea2..753d5cc 100644
--- a/core/modules/config/tests/config_test/src/ConfigTestListBuilder.php
+++ b/core/modules/config/tests/config_test/src/ConfigTestListBuilder.php
@@ -9,6 +9,7 @@
 
 use Drupal\Core\Config\Entity\ConfigEntityListBuilder;
 use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * Defines a class to build a listing of ConfigTest entities.
@@ -16,13 +17,14 @@
  * @see \Drupal\config_test\Entity\ConfigTest
  */
 class ConfigTestListBuilder extends ConfigEntityListBuilder {
+  use StringTranslationTrait;
 
   /**
    * {@inheritdoc}
    */
   public function buildHeader() {
-    $header['label'] = t('Label');
-    $header['id'] = t('Machine name');
+    $header['label'] = $this->t('Label');
+    $header['id'] = $this->t('Machine name');
     return $header + parent::buildHeader();
   }