diff --git a/core/modules/aggregator/src/Tests/FeedParserTest.php b/core/modules/aggregator/src/Tests/FeedParserTest.php
index a6d44c7..ab6aaaf 100644
--- a/core/modules/aggregator/src/Tests/FeedParserTest.php
+++ b/core/modules/aggregator/src/Tests/FeedParserTest.php
@@ -20,7 +20,7 @@ protected function setUp() {
     // Do not delete old aggregator items during these tests, since our sample
     // feeds have hardcoded dates in them (which may be expired when this test
     // is run).
-    $this->container->get('config.factory')->get('aggregator.settings')->set('items.expire', AGGREGATOR_CLEAR_NEVER)->save();
+    $this->config('aggregator.settings')->set('items.expire', AGGREGATOR_CLEAR_NEVER)->save();
     // Reset any reader cache between tests.
     Reader::reset();
     // Set our bridge extension manager to Zend Feed.
diff --git a/core/modules/block/src/Tests/BlockTest.php b/core/modules/block/src/Tests/BlockTest.php
index 6140404..9c30e10 100644
--- a/core/modules/block/src/Tests/BlockTest.php
+++ b/core/modules/block/src/Tests/BlockTest.php
@@ -190,7 +190,7 @@ function testBlock() {
   public function testBlockThemeSelector() {
     // Install all themes.
     \Drupal::service('theme_handler')->install(array('bartik', 'seven'));
-    $theme_settings = $this->container->get('config.factory')->get('system.theme');
+    $theme_settings = $this->config('system.theme');
     foreach (array('bartik', 'classy', 'seven') as $theme) {
       $this->drupalGet('admin/structure/block/list/' . $theme);
       $this->assertTitle(t('Block layout') . ' | Drupal');
diff --git a/core/modules/block_content/src/Tests/BlockContentTypeTest.php b/core/modules/block_content/src/Tests/BlockContentTypeTest.php
index 632c12a..60f1210 100644
--- a/core/modules/block_content/src/Tests/BlockContentTypeTest.php
+++ b/core/modules/block_content/src/Tests/BlockContentTypeTest.php
@@ -149,7 +149,7 @@ public function testsBlockContentAddTypes() {
     // Install all themes.
     \Drupal::service('theme_handler')->install(array('bartik', 'seven'));
     $themes = array('bartik', 'seven', 'classy');
-    $theme_settings = $this->container->get('config.factory')->get('system.theme');
+    $theme_settings = $this->config('system.theme');
     foreach ($themes as $default_theme) {
       // Change the default theme.
       $theme_settings->set('default', $default_theme)->save();
diff --git a/core/modules/ckeditor/src/Tests/CKEditorTest.php b/core/modules/ckeditor/src/Tests/CKEditorTest.php
index f5a637b..e81caf2 100644
--- a/core/modules/ckeditor/src/Tests/CKEditorTest.php
+++ b/core/modules/ckeditor/src/Tests/CKEditorTest.php
@@ -264,7 +264,7 @@ function testBuildContentsCssJSSetting() {
 
     // Enable the Bartik theme, which specifies a CKEditor stylesheet.
     \Drupal::service('theme_handler')->install(['bartik']);
-    $this->config('system.theme')->set('default', 'bartik');
+    $this->config('system.theme')->set('default', 'bartik')->save();
     $expected[] = file_create_url('core/themes/bartik/css/ckeditor-iframe.css');
     $this->assertIdentical($expected, $this->ckeditor->buildContentsCssJSSetting($editor), '"contentsCss" configuration part of JS settings built correctly while a theme providing a CKEditor stylesheet exists.');
   }
diff --git a/core/modules/config/src/Tests/ConfigCRUDTest.php b/core/modules/config/src/Tests/ConfigCRUDTest.php
index 1c1ac65..25391fe 100644
--- a/core/modules/config/src/Tests/ConfigCRUDTest.php
+++ b/core/modules/config/src/Tests/ConfigCRUDTest.php
@@ -44,6 +44,7 @@ class ConfigCRUDTest extends KernelTestBase {
    */
   function testCRUD() {
     $storage = $this->container->get('config.storage');
+    $config_factory = $this->container->get('config.factory');
     $name = 'config_test.crud';
 
     $config = $this->config($name);
@@ -73,9 +74,9 @@ function testCRUD() {
     $this->assertIdentical($config->isNew(), FALSE);
 
     // Pollute the config factory static cache.
-    $this->container->get('config.factory')->setOverrideState(FALSE);
-    \Drupal::config($name);
-    $this->container->get('config.factory')->setOverrideState(TRUE);
+    $config_factory->setOverrideState(FALSE);
+    $config_factory->get($name);
+    $config_factory->setOverrideState(TRUE);
 
     // Delete the configuration object.
     $config->delete();
@@ -86,9 +87,9 @@ function testCRUD() {
 
     // Verify that all copies of the configuration has been removed from the
     // static cache.
-    $this->container->get('config.factory')->setOverrideState(FALSE);
-    $this->assertIdentical(\Drupal::config($name)->isNew(), TRUE);
-    $this->container->get('config.factory')->setOverrideState(TRUE);
+    $config_factory->setOverrideState(FALSE);
+    $this->assertIdentical($config_factory->get($name)->isNew(), TRUE);
+    $config_factory->setOverrideState(TRUE);
 
     // Verify the active configuration contains no value.
     $actual_data = $storage->read($name);
@@ -128,25 +129,24 @@ function testCRUD() {
 
     // Test renaming when config.factory does not have the object in its static
     // cache.
-    $config_factory = $this->container->get('config.factory');
     $name = 'config_test.crud_rename';
     // Turn off overrides and pollute the non-overrides static cache.
     $config_factory->setOverrideState(FALSE);
-    \Drupal::config($name);
+    $config_factory->get($name);
     // Turn on overrides and pollute the overrides static cache.
     $config_factory->setOverrideState(TRUE);
-    $config = \Drupal::config($name);
+    $config = $config_factory->get($name);
     // Rename and ensure that happened properly.
     $new_name = 'config_test.crud_rename_no_cache';
     $config_factory->rename($name, $new_name);
-    $renamed_config = \Drupal::config($new_name);
+    $renamed_config = $config_factory->get($new_name);
     $this->assertIdentical($renamed_config->get(), $config->get());
     $this->assertIdentical($renamed_config->isNew(), FALSE);
     // Ensure the overrides static cache has been cleared.
-    $this->assertIdentical(\Drupal::config($name)->isNew(), TRUE);
+    $this->assertIdentical($config_factory->get($name)->isNew(), TRUE);
     // Ensure the non-overrides static cache has been cleared.
     $config_factory->setOverrideState(FALSE);
-    $this->assertIdentical(\Drupal::config($name)->isNew(), TRUE);
+    $this->assertIdentical($config_factory->get($name)->isNew(), TRUE);
     $config_factory->setOverrideState(TRUE);
 
     // Merge data into the configuration object.
diff --git a/core/modules/config/src/Tests/ConfigImportAllTest.php b/core/modules/config/src/Tests/ConfigImportAllTest.php
index de8e607..e1c2ed1 100644
--- a/core/modules/config/src/Tests/ConfigImportAllTest.php
+++ b/core/modules/config/src/Tests/ConfigImportAllTest.php
@@ -140,11 +140,10 @@ public function testInstallUninstall() {
     // conformance. Ensures all imported default configuration is valid when
     // all modules are enabled.
     $names = $this->container->get('config.storage')->listAll();
-    $factory = $this->container->get('config.factory');
     /** @var \Drupal\Core\Config\TypedConfigManagerInterface $typed_config */
     $typed_config = $this->container->get('config.typed');
     foreach ($names as $name) {
-      $config = $factory->get($name);
+      $config = $this->config($name);
       $this->assertConfigSchema($typed_config, $name, $config->get());
     }
   }
diff --git a/core/modules/config/src/Tests/ConfigOtherModuleTest.php b/core/modules/config/src/Tests/ConfigOtherModuleTest.php
index 72a332e..5737d78 100644
--- a/core/modules/config/src/Tests/ConfigOtherModuleTest.php
+++ b/core/modules/config/src/Tests/ConfigOtherModuleTest.php
@@ -25,7 +25,7 @@ public function testInstallOtherModuleFirst() {
     // Check that the config entity doesn't exist before the config_test module
     // is enabled. We cannot use the entity system because the config_test
     // entity type does not exist.
-    $config = $this->container->get('config.factory')->get('config_test.dynamic.other_module_test');
+    $config = $this->config('config_test.dynamic.other_module_test');
     $this->assertTrue($config->isNew(), 'Default configuration for other modules is not installed if that module is not enabled.');
 
     // Install the module that provides the entity type. This installs the
@@ -36,7 +36,7 @@ public function testInstallOtherModuleFirst() {
     // Uninstall the module that provides the entity type. This will remove the
     // default configuration.
     $this->uninstallModule('config_test');
-    $config = $this->container->get('config.factory')->get('config_test.dynamic.other_module_test');
+    $config = $this->config('config_test.dynamic.other_module_test');
     $this->assertTrue($config->isNew(), 'Default configuration for other modules is removed when the config entity provider is disabled.');
 
     // Install the module that provides the entity type again. This installs the
diff --git a/core/modules/config_translation/src/Tests/ConfigTranslationUiTest.php b/core/modules/config_translation/src/Tests/ConfigTranslationUiTest.php
index 35bfabe..3d0741b 100644
--- a/core/modules/config_translation/src/Tests/ConfigTranslationUiTest.php
+++ b/core/modules/config_translation/src/Tests/ConfigTranslationUiTest.php
@@ -510,9 +510,7 @@ public function testSourceAndTargetLanguage() {
     $this->assertResponse(403);
 
     // Set default language of site information to not-specified language (und).
-    $this->container
-      ->get('config.factory')
-      ->get('system.site')
+    $this->config('system.site')
       ->set('langcode', LanguageInterface::LANGCODE_NOT_SPECIFIED)
       ->save();
 
diff --git a/core/modules/content_translation/src/Tests/Views/ContentTranslationViewsUITest.php b/core/modules/content_translation/src/Tests/Views/ContentTranslationViewsUITest.php
index dc2328b..2ae4936 100644
--- a/core/modules/content_translation/src/Tests/Views/ContentTranslationViewsUITest.php
+++ b/core/modules/content_translation/src/Tests/Views/ContentTranslationViewsUITest.php
@@ -35,7 +35,7 @@ class ContentTranslationViewsUITest extends UITestBase {
    */
   public function testViewsUI() {
     $this->drupalGet('admin/structure/views/view/test_view/edit');
-    $this->assertTitle(t('@label (@table) | @site-name', array('@label' => 'Test view', '@table' => 'Views test data', '@site-name' => $this->container->get('config.factory')->get('system.site')->get('name'))));
+    $this->assertTitle(t('@label (@table) | @site-name', array('@label' => 'Test view', '@table' => 'Views test data', '@site-name' => $this->config('system.site')->get('name'))));
   }
 
 }
diff --git a/core/modules/datetime/src/Tests/DateTimeFieldTest.php b/core/modules/datetime/src/Tests/DateTimeFieldTest.php
index aa5239e..35811bc 100644
--- a/core/modules/datetime/src/Tests/DateTimeFieldTest.php
+++ b/core/modules/datetime/src/Tests/DateTimeFieldTest.php
@@ -320,7 +320,7 @@ function testDefaultValue() {
     $this->assertFieldByName('default_value_input[default_date]', '', 'The relative default value is empty in instance settings page');
 
     // Check if default_date has been stored successfully.
-    $config_entity = $this->container->get('config.factory')->get('field.field.node.date_content.' . $field_name)->get();
+    $config_entity = $this->config('field.field.node.date_content.' . $field_name)->get();
     $this->assertEqual($config_entity['default_value'][0], array('default_date_type' => 'now', 'default_date' => 'now'), 'Default value has been stored successfully');
 
     // Clear field cache in order to avoid stale cache values.
@@ -353,7 +353,7 @@ function testDefaultValue() {
     $this->assertFieldByName('default_value_input[default_date]', '+90 days', 'The relative default value is displayed in instance settings page');
 
     // Check if default_date has been stored successfully.
-    $config_entity = $this->container->get('config.factory')->get('field.field.node.date_content.' . $field_name)->get();
+    $config_entity = $this->config('field.field.node.date_content.' . $field_name)->get();
     $this->assertEqual($config_entity['default_value'][0], array('default_date_type' => 'relative', 'default_date' => '+90 days'), 'Default value has been stored successfully');
 
     // Clear field cache in order to avoid stale cache values.
@@ -376,7 +376,7 @@ function testDefaultValue() {
     $this->assertFieldByName('default_value_input[default_date]', '', 'The relative default value is empty in instance settings page');
 
     // Check if default_date has been stored successfully.
-    $config_entity = $this->container->get('config.factory')->get('field.field.node.date_content.' . $field_name)->get();
+    $config_entity = $this->config('field.field.node.date_content.' . $field_name)->get();
     $this->assertTrue(empty($config_entity['default_value']), 'Empty default value has been stored successfully');
 
     // Clear field cache in order to avoid stale cache values.
diff --git a/core/modules/entity_reference/src/Tests/EntityReferenceFieldDefaultValueTest.php b/core/modules/entity_reference/src/Tests/EntityReferenceFieldDefaultValueTest.php
index 2a5d1b6..38bc069 100644
--- a/core/modules/entity_reference/src/Tests/EntityReferenceFieldDefaultValueTest.php
+++ b/core/modules/entity_reference/src/Tests/EntityReferenceFieldDefaultValueTest.php
@@ -84,7 +84,7 @@ function testEntityReferenceDefaultValue() {
     $this->assertRaw('name="default_value_input[' . $field_name . '][0][target_id]" value="' . $referenced_node->getTitle() .' (' .$referenced_node->id() . ')', 'The default value is selected in instance settings page');
 
     // Check if the ID has been converted to UUID in config entity.
-    $config_entity = $this->container->get('config.factory')->get('field.field.node.reference_content.' . $field_name)->get();
+    $config_entity = $this->config('field.field.node.reference_content.' . $field_name)->get();
     $this->assertTrue(isset($config_entity['default_value'][0]['target_uuid']), 'Default value contains target_uuid property');
     $this->assertEqual($config_entity['default_value'][0]['target_uuid'], $referenced_node->uuid(), 'Content uuid and config entity uuid are the same');
     // Ensure the configuration has the expected dependency on the entity that
diff --git a/core/modules/file/src/Tests/DeleteTest.php b/core/modules/file/src/Tests/DeleteTest.php
index f39239f..5f0acc8 100644
--- a/core/modules/file/src/Tests/DeleteTest.php
+++ b/core/modules/file/src/Tests/DeleteTest.php
@@ -60,7 +60,7 @@ function testInUse() {
     // configuration value.
     db_update('file_managed')
       ->fields(array(
-        'changed' => REQUEST_TIME - ($this->container->get('config.factory')->get('system.file')->get('temporary_maximum_age') + 1),
+        'changed' => REQUEST_TIME - ($this->config('system.file')->get('temporary_maximum_age') + 1),
       ))
       ->condition('fid', $file->id())
       ->execute();
diff --git a/core/modules/file/src/Tests/FileFieldRevisionTest.php b/core/modules/file/src/Tests/FileFieldRevisionTest.php
index bf607ee..3c26f59 100644
--- a/core/modules/file/src/Tests/FileFieldRevisionTest.php
+++ b/core/modules/file/src/Tests/FileFieldRevisionTest.php
@@ -117,7 +117,7 @@ function testRevisions() {
     // configuration value.
     db_update('file_managed')
       ->fields(array(
-        'changed' => REQUEST_TIME - ($this->container->get('config.factory')->get('system.file')->get('temporary_maximum_age') + 1),
+        'changed' => REQUEST_TIME - ($this->config('system.file')->get('temporary_maximum_age') + 1),
       ))
       ->condition('fid', $node_file_r3->id())
       ->execute();
@@ -133,7 +133,7 @@ function testRevisions() {
     // configuration value.
     db_update('file_managed')
       ->fields(array(
-        'changed' => REQUEST_TIME - ($this->container->get('config.factory')->get('system.file')->get('temporary_maximum_age') + 1),
+        'changed' => REQUEST_TIME - ($this->config('system.file')->get('temporary_maximum_age') + 1),
       ))
       ->condition('fid', $node_file_r1->id())
       ->execute();
diff --git a/core/modules/file/src/Tests/UsageTest.php b/core/modules/file/src/Tests/UsageTest.php
index ba5b3b3..da96c47 100644
--- a/core/modules/file/src/Tests/UsageTest.php
+++ b/core/modules/file/src/Tests/UsageTest.php
@@ -128,7 +128,7 @@ function createTempFiles() {
     db_update('file_managed')
       ->fields(array(
         'status' => 0,
-        'changed' => REQUEST_TIME - $this->container->get('config.factory')->get('system.file')->get('temporary_maximum_age') - 1,
+        'changed' => REQUEST_TIME - $this->config('system.file')->get('temporary_maximum_age') - 1,
       ))
       ->condition('fid', $temp_old->id())
       ->execute();
@@ -145,7 +145,7 @@ function createTempFiles() {
     // Permanent file that is old.
     $perm_old = file_save_data('');
     db_update('file_managed')
-      ->fields(array('changed' => REQUEST_TIME - $this->container->get('config.factory')->get('system.file')->get('temporary_maximum_age') - 1))
+      ->fields(array('changed' => REQUEST_TIME - $this->config('system.file')->get('temporary_maximum_age') - 1))
       ->condition('fid', $temp_old->id())
       ->execute();
     $this->assertTrue(file_exists($perm_old->getFileUri()), 'Old permanent file was created correctly.');
diff --git a/core/modules/language/src/Tests/LanguageConfigurationTest.php b/core/modules/language/src/Tests/LanguageConfigurationTest.php
index 32f70e6..27abc6b 100644
--- a/core/modules/language/src/Tests/LanguageConfigurationTest.php
+++ b/core/modules/language/src/Tests/LanguageConfigurationTest.php
@@ -45,7 +45,7 @@ function testLanguageConfiguration() {
     $this->assertText('French');
     $this->assertUrl(\Drupal::url('language.admin_overview', [], ['absolute' => TRUE]), [], 'Correct page redirection.');
     // Langcode for Languages is always 'en'.
-    $language = $this->container->get('config.factory')->get('language.entity.fr')->get();
+    $language = $this->config('language.entity.fr')->get();
     $this->assertEqual($language['langcode'], 'en');
 
     // Check if the Default English language has no path prefix.
@@ -107,7 +107,7 @@ function testLanguageConfiguration() {
       'predefined_langcode' => 'de',
     );
     $this->drupalPostForm('admin/config/regional/language/add', $edit, 'Add language');
-    $language = $this->container->get('config.factory')->get('language.entity.de')->get();
+    $language = $this->config('language.entity.de')->get();
     $this->assertEqual($language['langcode'], 'en');
   }
 
diff --git a/core/modules/language/src/Tests/LanguageNegotiationInfoTest.php b/core/modules/language/src/Tests/LanguageNegotiationInfoTest.php
index 60fc384..d96e310 100644
--- a/core/modules/language/src/Tests/LanguageNegotiationInfoTest.php
+++ b/core/modules/language/src/Tests/LanguageNegotiationInfoTest.php
@@ -106,7 +106,7 @@ function testInfoAlterations() {
       'language_test.language_negotiation_info_alter' => TRUE,
     ));
 
-    $negotiation = $this->container->get('config.factory')->get('language.types')->get('negotiation.' . $type . '.enabled');
+    $negotiation = $this->config('language.types')->get('negotiation.' . $type . '.enabled');
     $this->assertFalse(isset($negotiation[$interface_method_id]), 'Interface language negotiation method removed from the stored settings.');
 
     $this->drupalGet('admin/config/regional/language/detection');
@@ -149,7 +149,7 @@ function testInfoAlterations() {
 
     // Check that unavailable language negotiation methods are not present in
     // the negotiation settings.
-    $negotiation = $this->container->get('config.factory')->get('language.types')->get('negotiation.' . $type . '.enabled');
+    $negotiation = $this->config('language.types')->get('negotiation.' . $type . '.enabled');
     $this->assertFalse(isset($negotiation[$test_method_id]), 'The disabled test language negotiation method is not part of the content language negotiation settings.');
 
     // Check that configuration page presents the correct options and settings.
@@ -164,7 +164,7 @@ protected function checkFixedLanguageTypes() {
     $configurable = $this->languageManager()->getLanguageTypes();
     foreach ($this->languageManager()->getDefinedLanguageTypesInfo() as $type => $info) {
       if (!in_array($type, $configurable) && isset($info['fixed'])) {
-        $negotiation = $this->container->get('config.factory')->get('language.types')->get('negotiation.' . $type . '.enabled');
+        $negotiation = $this->config('language.types')->get('negotiation.' . $type . '.enabled');
         $equal = count($info['fixed']) == count($negotiation);
         while ($equal && list($id) = each($negotiation)) {
           list(, $info_id) = each($info['fixed']);
diff --git a/core/modules/node/src/Tests/NodeAccessTest.php b/core/modules/node/src/Tests/NodeAccessTest.php
index 0e4978b..b96dfa8 100644
--- a/core/modules/node/src/Tests/NodeAccessTest.php
+++ b/core/modules/node/src/Tests/NodeAccessTest.php
@@ -19,7 +19,7 @@ class NodeAccessTest extends NodeTestBase {
   protected function setUp() {
     parent::setUp();
     // Clear permissions for authenticated users.
-    $this->container->get('config.factory')->get('user.role.' . DRUPAL_AUTHENTICATED_RID)->set('permissions', array())->save();
+    $this->config('user.role.' . DRUPAL_AUTHENTICATED_RID)->set('permissions', array())->save();
   }
 
   /**
diff --git a/core/modules/node/src/Tests/Views/FrontPageTest.php b/core/modules/node/src/Tests/Views/FrontPageTest.php
index ac93dd3..34ff389 100644
--- a/core/modules/node/src/Tests/Views/FrontPageTest.php
+++ b/core/modules/node/src/Tests/Views/FrontPageTest.php
@@ -43,8 +43,7 @@ protected function setUp() {
    */
   public function testFrontPage() {
     $site_name = $this->randomMachineName();
-    $this->container->get('config.factory')
-      ->get('system.site')
+    $this->config('system.site')
       ->set('name', $site_name)
       ->save();
 
diff --git a/core/modules/shortcut/src/Tests/ShortcutLinksTest.php b/core/modules/shortcut/src/Tests/ShortcutLinksTest.php
index 162da37..d9cb0c7 100644
--- a/core/modules/shortcut/src/Tests/ShortcutLinksTest.php
+++ b/core/modules/shortcut/src/Tests/ShortcutLinksTest.php
@@ -101,7 +101,7 @@ public function testShortcutLinkAdd() {
   public function testShortcutQuickLink() {
     \Drupal::service('theme_handler')->install(array('seven'));
     $this->config('system.theme')->set('admin', 'seven')->save();
-    $this->container->get('config.factory')->get('node.settings')->set('use_admin_theme', '1')->save();
+    $this->config('node.settings')->set('use_admin_theme', '1')->save();
     $this->container->get('router.builder')->rebuild();
 
     $this->drupalLogin($this->root_user);
diff --git a/core/modules/simpletest/src/Tests/KernelTestBaseTest.php b/core/modules/simpletest/src/Tests/KernelTestBaseTest.php
index 1fe5497..270e08c 100644
--- a/core/modules/simpletest/src/Tests/KernelTestBaseTest.php
+++ b/core/modules/simpletest/src/Tests/KernelTestBaseTest.php
@@ -285,7 +285,7 @@ function testEnableModulesTheme() {
    * Tests that there is no theme by default.
    */
   function testNoThemeByDefault() {
-    $themes = $this->container->get('config.factory')->get('core.extension')->get('theme');
+    $themes = $this->config('core.extension')->get('theme');
     $this->assertEqual($themes, array());
 
     $extensions = $this->container->get('config.storage')->read('core.extension');
diff --git a/core/modules/statistics/src/Tests/Views/IntegrationTest.php b/core/modules/statistics/src/Tests/Views/IntegrationTest.php
index b26745a..d83a387 100644
--- a/core/modules/statistics/src/Tests/Views/IntegrationTest.php
+++ b/core/modules/statistics/src/Tests/Views/IntegrationTest.php
@@ -59,7 +59,7 @@ protected function setUp() {
     $this->node = $this->drupalCreateNode(array('type' => 'page'));
 
     // Enable access logging.
-    $this->container->get('config.factory')->get('statistics.settings')
+    $this->config('statistics.settings')
       ->set('access_log.enabled', 1)
       ->set('count_content_views', 1)
       ->save();
diff --git a/core/modules/system/src/Tests/Batch/PageTest.php b/core/modules/system/src/Tests/Batch/PageTest.php
index 42800b7..1dd7628 100644
--- a/core/modules/system/src/Tests/Batch/PageTest.php
+++ b/core/modules/system/src/Tests/Batch/PageTest.php
@@ -30,7 +30,7 @@ function testBatchProgressPageTheme() {
     // Make sure that the page which starts the batch (an administrative page)
     // is using a different theme than would normally be used by the batch API.
     $this->container->get('theme_handler')->install(array('seven', 'bartik'));
-    $this->container->get('config.factory')->get('system.theme')
+    $this->config('system.theme')
       ->set('default', 'bartik')
       ->set('admin', 'seven')
       ->save();
diff --git a/core/modules/system/src/Tests/Entity/ConfigEntityImportTest.php b/core/modules/system/src/Tests/Entity/ConfigEntityImportTest.php
index c266aa4..f7036d3 100644
--- a/core/modules/system/src/Tests/Entity/ConfigEntityImportTest.php
+++ b/core/modules/system/src/Tests/Entity/ConfigEntityImportTest.php
@@ -220,7 +220,7 @@ public function assertConfigUpdateImport($name, $original_data, $custom_data) {
     $this->container->get('config.storage.staging')->write($name, $custom_data);
 
     // Verify the active configuration still returns the default values.
-    $config = $this->container->get('config.factory')->get($name);
+    $config = $this->config($name);
     $this->assertIdentical($config->get(), $original_data);
 
     // Import.
@@ -228,7 +228,7 @@ public function assertConfigUpdateImport($name, $original_data, $custom_data) {
 
     // Verify the values were updated.
     $this->container->get('config.factory')->reset($name);
-    $config = $this->container->get('config.factory')->get($name);
+    $config = $this->config($name);
     $this->assertIdentical($config->get(), $custom_data);
   }
 
diff --git a/core/modules/system/src/Tests/Form/ConfirmFormTest.php b/core/modules/system/src/Tests/Form/ConfirmFormTest.php
index fcb4e61..ffcc44a 100644
--- a/core/modules/system/src/Tests/Form/ConfirmFormTest.php
+++ b/core/modules/system/src/Tests/Form/ConfirmFormTest.php
@@ -26,7 +26,7 @@ class ConfirmFormTest extends WebTestBase {
   function testConfirmForm() {
     // Test the building of the form.
     $this->drupalGet('form-test/confirm-form');
-    $site_name = $this->container->get('config.factory')->get('system.site')->get('name');
+    $site_name = $this->config('system.site')->get('name');
     $this->assertTitle(t('ConfirmFormTestForm::getQuestion(). | @site-name', array('@site-name' => $site_name)), 'The question was found as the page title.');
     $this->assertText(t('ConfirmFormTestForm::getDescription().'), 'The description was used.');
     $this->assertFieldByXPath('//input[@id="edit-submit"]', t('ConfirmFormTestForm::getConfirmText().'), 'The confirm text was used.');
diff --git a/core/modules/system/src/Tests/Menu/MenuRouterTest.php b/core/modules/system/src/Tests/Menu/MenuRouterTest.php
index fbf9f77..61ec849 100644
--- a/core/modules/system/src/Tests/Menu/MenuRouterTest.php
+++ b/core/modules/system/src/Tests/Menu/MenuRouterTest.php
@@ -243,7 +243,7 @@ public function testThemeIntegration() {
 
     $theme_handler = $this->container->get('theme_handler');
     $theme_handler->install(array($this->default_theme, $this->admin_theme));
-    $this->container->get('config.factory')->get('system.theme')
+    $this->config('system.theme')
       ->set('default', $this->default_theme)
       ->set('admin', $this->admin_theme)
       ->save();
diff --git a/core/modules/system/src/Tests/System/TokenReplaceUnitTest.php b/core/modules/system/src/Tests/System/TokenReplaceUnitTest.php
index 2f2b4f0..9a51f2f 100644
--- a/core/modules/system/src/Tests/System/TokenReplaceUnitTest.php
+++ b/core/modules/system/src/Tests/System/TokenReplaceUnitTest.php
@@ -85,7 +85,7 @@ public function testSystemSiteTokenReplacement() {
     $safe_slogan = Xss::filterAdmin($slogan);
 
     // Set a few site variables.
-    $config = $this->container->get('config.factory')->get('system.site');
+    $config = $this->config('system.site');
     $config
       ->set('name', '<strong>Drupal<strong>')
       ->set('slogan', $slogan)
diff --git a/core/modules/update/src/Tests/UpdateDeleteFileIfStaleTest.php b/core/modules/update/src/Tests/UpdateDeleteFileIfStaleTest.php
index 7cafd11..9de98a4 100644
--- a/core/modules/update/src/Tests/UpdateDeleteFileIfStaleTest.php
+++ b/core/modules/update/src/Tests/UpdateDeleteFileIfStaleTest.php
@@ -39,8 +39,7 @@ function testUpdateDeleteFileIfStale() {
     // request, so the beginning of request will be before the file changes and
     // REQUEST_TIME - $filectime is negative. Set the maximum age to a number
     // even smaller than that.
-    $this->container->get('config.factory')
-      ->get('system.file')
+    $this->config('system.file')
       ->set('temporary_maximum_age', -100000)
       ->save();
 
diff --git a/core/modules/user/src/Tests/UserAccountFormFieldsTest.php b/core/modules/user/src/Tests/UserAccountFormFieldsTest.php
index 384fee3..679eec0 100644
--- a/core/modules/user/src/Tests/UserAccountFormFieldsTest.php
+++ b/core/modules/user/src/Tests/UserAccountFormFieldsTest.php
@@ -55,8 +55,7 @@ function testUserRegistrationForm() {
     $this->installConfig(array('user'));
 
     // Disable email confirmation to unlock the password field.
-    $this->container->get('config.factory')
-      ->get('user.settings')
+    $this->config('user.settings')
       ->set('verify_mail', FALSE)
       ->save();
 
diff --git a/core/modules/user/src/Tests/UserPictureTest.php b/core/modules/user/src/Tests/UserPictureTest.php
index 639c382..13feb0f 100644
--- a/core/modules/user/src/Tests/UserPictureTest.php
+++ b/core/modules/user/src/Tests/UserPictureTest.php
@@ -65,7 +65,7 @@ function testCreateDeletePicture() {
     // configuration value.
     db_update('file_managed')
       ->fields(array(
-        'changed' => REQUEST_TIME - ($this->container->get('config.factory')->get('system.file')->get('temporary_maximum_age') + 1),
+        'changed' => REQUEST_TIME - ($this->config('system.file')->get('temporary_maximum_age') + 1),
       ))
       ->condition('fid', $file->id())
       ->execute();
@@ -91,14 +91,14 @@ function testPictureOnNodeComment() {
     $node = $this->drupalCreateNode(array('type' => 'article'));
 
     // Enable user pictures on nodes.
-    $this->container->get('config.factory')->get('system.theme.global')->set('features.node_user_picture', TRUE)->save();
+    $this->config('system.theme.global')->set('features.node_user_picture', TRUE)->save();
 
     // Verify that the image is displayed on the user account page.
     $this->drupalGet('node/' . $node->id());
     $this->assertRaw(file_uri_target($file->getFileUri()), 'User picture found on node page.');
 
     // Enable user pictures on comments, instead of nodes.
-    $this->container->get('config.factory')->get('system.theme.global')
+    $this->config('system.theme.global')
       ->set('features.node_user_picture', FALSE)
       ->set('features.comment_user_picture', TRUE)
       ->save();
@@ -113,7 +113,7 @@ function testPictureOnNodeComment() {
     $this->assertRaw(file_uri_target($file->getFileUri()), 'User picture found on comment.');
 
     // Disable user pictures on comments and nodes.
-    $this->container->get('config.factory')->get('system.theme.global')
+    $this->config('system.theme.global')
       ->set('features.node_user_picture', FALSE)
       ->set('features.comment_user_picture', FALSE)
       ->save();
diff --git a/core/modules/user/src/Tests/Views/HandlerArgumentUserUidTest.php b/core/modules/user/src/Tests/Views/HandlerArgumentUserUidTest.php
index 2327c58..01373fb 100644
--- a/core/modules/user/src/Tests/Views/HandlerArgumentUserUidTest.php
+++ b/core/modules/user/src/Tests/Views/HandlerArgumentUserUidTest.php
@@ -41,7 +41,7 @@ public function testArgumentTitle() {
     $view->destroy();
 
     // Tests the anonymous user.
-    $anonymous = $this->container->get('config.factory')->get('user.settings')->get('anonymous');
+    $anonymous = $this->config('user.settings')->get('anonymous');
     $this->executeView($view, array(0));
     $this->assertEqual($view->getTitle(), $anonymous);
     $view->destroy();
diff --git a/core/modules/views/src/Tests/Plugin/DisplayFeedTest.php b/core/modules/views/src/Tests/Plugin/DisplayFeedTest.php
index 97e6e99..cef9bab 100644
--- a/core/modules/views/src/Tests/Plugin/DisplayFeedTest.php
+++ b/core/modules/views/src/Tests/Plugin/DisplayFeedTest.php
@@ -47,7 +47,7 @@ public function testFeedOutput() {
 
     // Test the site name setting.
     $site_name = $this->randomMachineName();
-    $this->container->get('config.factory')->get('system.site')->set('name', $site_name)->save();
+    $this->config('system.site')->set('name', $site_name)->save();
 
     $this->drupalGet('test-feed-display.xml');
     $result = $this->xpath('//title');
diff --git a/core/profiles/standard/src/Tests/StandardTest.php b/core/profiles/standard/src/Tests/StandardTest.php
index 567cb9f..f8d4999 100644
--- a/core/profiles/standard/src/Tests/StandardTest.php
+++ b/core/profiles/standard/src/Tests/StandardTest.php
@@ -98,11 +98,10 @@ function testStandard() {
     // conformance. Ensures all imported default configuration is valid when
     // standard profile modules are enabled.
     $names = $this->container->get('config.storage')->listAll();
-    $factory = $this->container->get('config.factory');
     /** @var \Drupal\Core\Config\TypedConfigManagerInterface $typed_config */
     $typed_config = $this->container->get('config.typed');
     foreach ($names as $name) {
-      $config = $factory->get($name);
+      $config = $this->config($name);
       $this->assertConfigSchema($typed_config, $name, $config->get());
     }