diff --git a/core/modules/block/src/Tests/BlockInterfaceTest.php b/core/modules/block/src/Tests/BlockInterfaceTest.php
index 7215765..f7af9fe 100644
--- a/core/modules/block/src/Tests/BlockInterfaceTest.php
+++ b/core/modules/block/src/Tests/BlockInterfaceTest.php
@@ -109,7 +109,7 @@ public function testBlockInterface() {
     $actual_form = $display_block->buildConfigurationForm(array(), $form_state);
     // Remove the visibility sections, as that just tests condition plugins.
     unset($actual_form['visibility'], $actual_form['visibility_tabs']);
-    $this->assertIdentical($actual_form, $expected_form, 'Only the expected form elements were present.');
+    $this->assertIdentical($this->castSafeStrings($actual_form), $this->castSafeStrings($expected_form), 'Only the expected form elements were present.');
 
     $expected_build = array(
       '#children' => 'My custom display message.',
diff --git a/core/modules/block_content/src/Tests/BlockContentListTest.php b/core/modules/block_content/src/Tests/BlockContentListTest.php
index aeed4dc..8b77d1a 100644
--- a/core/modules/block_content/src/Tests/BlockContentListTest.php
+++ b/core/modules/block_content/src/Tests/BlockContentListTest.php
@@ -46,7 +46,7 @@ public function testListing() {
     // Test the contents of each th cell.
     $expected_items = array(t('Block description'), t('Operations'));
     foreach ($elements as $key => $element) {
-      $this->assertIdentical((string) $element[0], $expected_items[$key]);
+      $this->assertEqual($element[0], $expected_items[$key]);
     }
 
     $label = 'Antelope';
diff --git a/core/modules/block_content/src/Tests/BlockContentListViewsTest.php b/core/modules/block_content/src/Tests/BlockContentListViewsTest.php
index ba84f2b..34a5f22 100644
--- a/core/modules/block_content/src/Tests/BlockContentListViewsTest.php
+++ b/core/modules/block_content/src/Tests/BlockContentListViewsTest.php
@@ -42,7 +42,7 @@ public function testListing() {
     $this->assertEqual(count($elements), 4, 'Correct number of table header cells found.');
 
     // Test the contents of each th cell.
-    $expected_items = [t('Block description'), t('Block type'), t('Updated'), t('Operations')];
+    $expected_items = ['Block description', 'Block type', 'Updated', 'Operations'];
     foreach ($elements as $key => $element) {
       if ($element->xpath('a')) {
         $this->assertIdentical(trim((string) $element->xpath('a')[0]), $expected_items[$key]);
diff --git a/core/modules/breakpoint/src/Tests/BreakpointDiscoveryTest.php b/core/modules/breakpoint/src/Tests/BreakpointDiscoveryTest.php
index 0668c86..942239b 100644
--- a/core/modules/breakpoint/src/Tests/BreakpointDiscoveryTest.php
+++ b/core/modules/breakpoint/src/Tests/BreakpointDiscoveryTest.php
@@ -193,7 +193,7 @@ public function testBreakpointGroups() {
     );
     $breakpoint_groups = \Drupal::service('breakpoint.manager')->getGroups();
     // Ensure the order is as expected. Should be sorted by label.
-    $this->assertIdentical($expected, $breakpoint_groups);
+    $this->assertIdentical($expected, $this->castSafeStrings($breakpoint_groups));
 
     $expected = array(
       'breakpoint_theme_test' => 'theme',
diff --git a/core/modules/ckeditor/src/Tests/CKEditorAdminTest.php b/core/modules/ckeditor/src/Tests/CKEditorAdminTest.php
index ca1954f..6c5ee13 100644
--- a/core/modules/ckeditor/src/Tests/CKEditorAdminTest.php
+++ b/core/modules/ckeditor/src/Tests/CKEditorAdminTest.php
@@ -87,23 +87,23 @@ function testExistingFormat() {
           // Button groups
           array(
             array(
-              'name' => t('Formatting'),
+              'name' => 'Formatting',
               'items' => array('Bold', 'Italic',),
             ),
             array(
-              'name' => t('Links'),
+              'name' => 'Links',
               'items' => array('DrupalLink', 'DrupalUnlink',),
             ),
             array(
-              'name' => t('Lists'),
+              'name' => 'Lists',
               'items' => array('BulletedList', 'NumberedList',),
             ),
             array(
-              'name' => t('Media'),
+              'name' => 'Media',
               'items' => array('Blockquote', 'DrupalImage',),
             ),
             array(
-              'name' => t('Tools'),
+              'name' => 'Tools',
               'items' => array('Source',),
             ),
           ),
@@ -111,7 +111,7 @@ function testExistingFormat() {
       ),
       'plugins' => array(),
     );
-    $this->assertIdentical($ckeditor->getDefaultSettings(), $expected_default_settings);
+    $this->assertIdentical($this->castSafeStrings($ckeditor->getDefaultSettings()), $expected_default_settings);
 
     // Keep the "CKEditor" editor selected and click the "Configure" button.
     $this->drupalPostAjaxForm(NULL, $edit, 'editor_configure');
@@ -279,7 +279,7 @@ function testNewFormat() {
     $expected_settings['plugins']['stylescombo']['styles'] = '';
     $editor = entity_load('editor', 'amazing_format');
     $this->assertTrue($editor instanceof Editor, 'An Editor config entity exists now.');
-    $this->assertIdentical($expected_settings, $editor->getSettings(), 'The Editor config entity has the correct settings.');
+    $this->assertIdentical($this->castSafeStrings($expected_settings), $this->castSafeStrings($editor->getSettings()), 'The Editor config entity has the correct settings.');
   }
 
 }
diff --git a/core/modules/ckeditor/src/Tests/CKEditorLoadingTest.php b/core/modules/ckeditor/src/Tests/CKEditorLoadingTest.php
index 01b9081..1081eb9 100644
--- a/core/modules/ckeditor/src/Tests/CKEditorLoadingTest.php
+++ b/core/modules/ckeditor/src/Tests/CKEditorLoadingTest.php
@@ -107,12 +107,12 @@ function testLoading() {
     $expected = array('formats' => array('filtered_html' => array(
       'format' => 'filtered_html',
       'editor' => 'ckeditor',
-      'editorSettings' => $ckeditor_plugin->getJSSettings($editor),
+      'editorSettings' => $this->castSafeStrings($ckeditor_plugin->getJSSettings($editor)),
       'editorSupportsContentFiltering' => TRUE,
       'isXssSafe' => FALSE,
     )));
     $this->assertTrue($editor_settings_present, "Text Editor module's JavaScript settings are on the page.");
-    $this->assertIdentical($expected, $settings['editor'], "Text Editor module's JavaScript settings on the page are correct.");
+    $this->assertIdentical($expected, $this->castSafeStrings($settings['editor']), "Text Editor module's JavaScript settings on the page are correct.");
     $this->assertTrue($editor_js_present, 'Text Editor JavaScript is present.');
     $this->assertTrue(count($body) === 1, 'A body field exists.');
     $this->assertTrue(count($format_selector) === 1, 'A single text format selector exists on the page.');
@@ -138,12 +138,12 @@ function testLoading() {
         'filtered_html' => array(
           'format' => 'filtered_html',
           'editor' => 'ckeditor',
-          'editorSettings' => $ckeditor_plugin->getJSSettings($editor),
+          'editorSettings' => $this->castSafeStrings($ckeditor_plugin->getJSSettings($editor)),
           'editorSupportsContentFiltering' => TRUE,
           'isXssSafe' => FALSE,
     )));
     $this->assertTrue($editor_settings_present, "Text Editor module's JavaScript settings are on the page.");
-    $this->assertIdentical($expected, $settings['editor'], "Text Editor module's JavaScript settings on the page are correct.");
+    $this->assertIdentical($expected, $this->castSafeStrings($settings['editor']), "Text Editor module's JavaScript settings on the page are correct.");
     $this->assertTrue($editor_js_present, 'Text Editor JavaScript is present.');
     $this->assertTrue(in_array('ckeditor/drupal.ckeditor', explode(',', $settings['ajaxPageState']['libraries'])), 'CKEditor glue library is present.');
   }
diff --git a/core/modules/ckeditor/src/Tests/CKEditorTest.php b/core/modules/ckeditor/src/Tests/CKEditorTest.php
index d2a59bc..f842862 100644
--- a/core/modules/ckeditor/src/Tests/CKEditorTest.php
+++ b/core/modules/ckeditor/src/Tests/CKEditorTest.php
@@ -94,8 +94,9 @@ function testGetJSSettings() {
         'drupallink' => file_create_url('core/modules/ckeditor/js/plugins/drupallink/plugin.js'),
       ),
     );
+    $expected_config = $this->castSafeStrings($expected_config);
     ksort($expected_config);
-    $this->assertIdentical($expected_config, $this->ckeditor->getJSSettings($editor), 'Generated JS settings are correct for default configuration.');
+    $this->assertIdentical($expected_config, $this->castSafeStrings($this->ckeditor->getJSSettings($editor)), 'Generated JS settings are correct for default configuration.');
 
     // Customize the configuration: add button, have two contextually enabled
     // buttons, and configure a CKEditor plugin setting.
@@ -116,7 +117,7 @@ function testGetJSSettings() {
     $expected_config['drupalExternalPlugins']['llama_contextual_and_button'] = file_create_url('core/modules/ckeditor/tests/modules/js/llama_contextual_and_button.js');
     $expected_config['contentsCss'][] = file_create_url('core/modules/ckeditor/tests/modules/ckeditor_test.css');
     ksort($expected_config);
-    $this->assertIdentical($expected_config, $this->ckeditor->getJSSettings($editor), 'Generated JS settings are correct for customized configuration.');
+    $this->assertIdentical($expected_config, $this->castSafeStrings($this->ckeditor->getJSSettings($editor)), 'Generated JS settings are correct for customized configuration.');
 
     // Change the allowed HTML tags; the "allowedContent" and "format_tags"
     // settings for CKEditor should automatically be updated as well.
@@ -127,7 +128,7 @@ function testGetJSSettings() {
     $expected_config['allowedContent']['pre'] = array('attributes' => TRUE, 'styles' => FALSE, 'classes' => TRUE);
     $expected_config['allowedContent']['h3'] = array('attributes' => TRUE, 'styles' => FALSE, 'classes' => TRUE);
     $expected_config['format_tags'] = 'p;h2;h3;h4;h5;h6;pre';
-    $this->assertIdentical($expected_config, $this->ckeditor->getJSSettings($editor), 'Generated JS settings are correct for customized configuration.');
+    $this->assertIdentical($expected_config, $this->castSafeStrings($this->ckeditor->getJSSettings($editor)), 'Generated JS settings are correct for customized configuration.');
 
     // Disable the filter_html filter: allow *all *tags.
     $format->setFilterConfig('filter_html', array('status' => 0));
@@ -136,7 +137,7 @@ function testGetJSSettings() {
     $expected_config['allowedContent'] = TRUE;
     $expected_config['disallowedContent'] = FALSE;
     $expected_config['format_tags'] = 'p;h1;h2;h3;h4;h5;h6;pre';
-    $this->assertIdentical($expected_config, $this->ckeditor->getJSSettings($editor), 'Generated JS settings are correct for customized configuration.');
+    $this->assertIdentical($expected_config, $this->castSafeStrings($this->ckeditor->getJSSettings($editor)), 'Generated JS settings are correct for customized configuration.');
 
     // Enable the filter_test_restrict_tags_and_attributes filter.
     $format->setFilterConfig('filter_test_restrict_tags_and_attributes', array(
@@ -205,7 +206,7 @@ function testGetJSSettings() {
     );
     $expected_config['format_tags'] = 'p';
     ksort($expected_config);
-    $this->assertIdentical($expected_config, $this->ckeditor->getJSSettings($editor), 'Generated JS settings are correct for customized configuration.');
+    $this->assertIdentical($expected_config, $this->castSafeStrings($this->ckeditor->getJSSettings($editor)), 'Generated JS settings are correct for customized configuration.');
   }
 
   /**
@@ -216,7 +217,7 @@ function testBuildToolbarJSSetting() {
 
     // Default toolbar.
     $expected = $this->getDefaultToolbarConfig();
-    $this->assertIdentical($expected, $this->ckeditor->buildToolbarJSSetting($editor), '"toolbar" configuration part of JS settings built correctly for default toolbar.');
+    $this->assertIdentical($expected, $this->castSafeStrings($this->ckeditor->buildToolbarJSSetting($editor)), '"toolbar" configuration part of JS settings built correctly for default toolbar.');
 
     // Customize the configuration.
     $settings = $editor->getSettings();
@@ -224,7 +225,7 @@ function testBuildToolbarJSSetting() {
     $editor->setSettings($settings);
     $editor->save();
     $expected[0]['items'][] = 'Strike';
-    $this->assertIdentical($expected, $this->ckeditor->buildToolbarJSSetting($editor), '"toolbar" configuration part of JS settings built correctly for customized toolbar.');
+    $this->assertIdentical($expected, $this->castSafeStrings($this->ckeditor->buildToolbarJSSetting($editor)), '"toolbar" configuration part of JS settings built correctly for customized toolbar.');
 
     // Enable the editor_test module, customize further.
     $this->enableModules(array('ckeditor_test'));
@@ -236,7 +237,7 @@ function testBuildToolbarJSSetting() {
     $editor->save();
     $expected[0]['name'] = 'JunkScience';
     $expected[0]['items'][] = 'Llama';
-    $this->assertIdentical($expected, $this->ckeditor->buildToolbarJSSetting($editor), '"toolbar" configuration part of JS settings built correctly for customized toolbar with contrib module-provided CKEditor plugin.');
+    $this->assertIdentical($expected, $this->castSafeStrings($this->ckeditor->buildToolbarJSSetting($editor)), '"toolbar" configuration part of JS settings built correctly for customized toolbar with contrib module-provided CKEditor plugin.');
   }
 
   /**
@@ -442,23 +443,23 @@ protected function getDefaultDisallowedContentConfig() {
   protected function getDefaultToolbarConfig() {
     return array(
       array(
-        'name' => t('Formatting'),
+        'name' => 'Formatting',
         'items' => array('Bold', 'Italic',),
       ),
       array(
-        'name' => t('Links'),
+        'name' => 'Links',
         'items' => array('DrupalLink', 'DrupalUnlink',),
       ),
       array(
-        'name' => t('Lists'),
+        'name' => 'Lists',
         'items' => array('BulletedList', 'NumberedList',),
       ),
       array(
-        'name' => t('Media'),
+        'name' => 'Media',
         'items' => array('Blockquote', 'DrupalImage',),
       ),
       array(
-        'name' => t('Tools'),
+        'name' => 'Tools',
         'items' => array('Source',),
       ),
       '/',
diff --git a/core/modules/config/src/Tests/ConfigImportRenameValidationTest.php b/core/modules/config/src/Tests/ConfigImportRenameValidationTest.php
index 7f0d72e..e0b6a70 100644
--- a/core/modules/config/src/Tests/ConfigImportRenameValidationTest.php
+++ b/core/modules/config/src/Tests/ConfigImportRenameValidationTest.php
@@ -112,7 +112,7 @@ public function testRenameValidation() {
       $expected = array(
         SafeMarkup::format('Entity type mismatch on rename. @old_type not equal to @new_type for existing configuration @old_name and staged configuration @new_name.', array('@old_type' => 'node_type', '@new_type' => 'config_test', '@old_name' => 'node.type.' . $content_type->id(), '@new_name' => 'config_test.dynamic.' . $test_entity_id))
       );
-      $this->assertIdentical($expected, $this->configImporter->getErrors());
+      $this->assertEqual($expected, $this->configImporter->getErrors());
     }
   }
 
@@ -155,7 +155,7 @@ public function testRenameSimpleConfigValidation() {
       $expected = array(
         SafeMarkup::format('Rename operation for simple configuration. Existing configuration @old_name and staged configuration @new_name.', array('@old_name' => 'config_test.old', '@new_name' => 'config_test.new'))
       );
-      $this->assertIdentical($expected, $this->configImporter->getErrors());
+      $this->assertEqual($expected, $this->configImporter->getErrors());
     }
   }
 
diff --git a/core/modules/locale/src/Tests/LocaleImportFunctionalTest.php b/core/modules/locale/src/Tests/LocaleImportFunctionalTest.php
index 05af294..1c13517 100644
--- a/core/modules/locale/src/Tests/LocaleImportFunctionalTest.php
+++ b/core/modules/locale/src/Tests/LocaleImportFunctionalTest.php
@@ -238,8 +238,10 @@ public function testLanguageContext() {
       'langcode' => 'hr',
     ));
 
-    $this->assertIdentical(t('May', array(), array('langcode' => 'hr', 'context' => 'Long month name')), 'Svibanj', 'Long month name context is working.');
-    $this->assertIdentical(t('May', array(), array('langcode' => 'hr')), 'Svi.', 'Default context is working.');
+    // We cast the return value of t() to string so as to retrieve the
+    // translated value, rendered as a string.
+    $this->assertIdentical((string) t('May', array(), array('langcode' => 'hr', 'context' => 'Long month name')), 'Svibanj', 'Long month name context is working.');
+    $this->assertIdentical((string) t('May', array(), array('langcode' => 'hr')), 'Svi.', 'Default context is working.');
   }
 
   /**
@@ -254,7 +256,7 @@ public function testEmptyMsgstr() {
     ));
 
     $this->assertRaw(t('One translation file imported. %number translations were added, %update translations were updated and %delete translations were removed.', array('%number' => 1, '%update' => 0, '%delete' => 0)), 'The translation file was successfully imported.');
-    $this->assertIdentical(t('Operations', array(), array('langcode' => $langcode)), 'Műveletek', 'String imported and translated.');
+    $this->assertIdentical((string) t('Operations', array(), array('langcode' => $langcode)), 'Műveletek', 'String imported and translated.');
 
     // Try importing a .po file.
     $this->importPoFile($this->getPoFileWithEmptyMsgstr(), array(
diff --git a/core/modules/migrate_drupal/src/Tests/dependencies/MigrateDependenciesTest.php b/core/modules/migrate_drupal/src/Tests/dependencies/MigrateDependenciesTest.php
index 59caa80..d3a5574 100644
--- a/core/modules/migrate_drupal/src/Tests/dependencies/MigrateDependenciesTest.php
+++ b/core/modules/migrate_drupal/src/Tests/dependencies/MigrateDependenciesTest.php
@@ -69,7 +69,7 @@ public function testAggregatorMigrateDependencies() {
     $executable = new MigrateExecutable($migration, $this);
     $this->startCollectingMessages();
     $executable->import();
-    $this->assertIdentical($this->migrateMessages['error'], array(SafeMarkup::format('Migration @id did not meet the requirements. Missing migrations d6_aggregator_feed. requirements: d6_aggregator_feed.', array('@id' => $migration->id()))));
+    $this->assertEqual($this->migrateMessages['error'], array(SafeMarkup::format('Migration @id did not meet the requirements. Missing migrations d6_aggregator_feed. requirements: d6_aggregator_feed.', array('@id' => $migration->id()))));
     $this->collectMessages = FALSE;
   }
 
diff --git a/core/modules/node/src/Tests/Migrate/d6/MigrateNodeBuilderTest.php b/core/modules/node/src/Tests/Migrate/d6/MigrateNodeBuilderTest.php
index 4a5483a..21d130a 100644
--- a/core/modules/node/src/Tests/Migrate/d6/MigrateNodeBuilderTest.php
+++ b/core/modules/node/src/Tests/Migrate/d6/MigrateNodeBuilderTest.php
@@ -34,8 +34,8 @@ class MigrateNodeBuilderTest extends MigrateDrupal6TestBase {
   protected function assertEntity($id, $label) {
     $migration = $this->builtMigrations[$id];
     $this->assertTrue($migration instanceof Migration);
-    $this->assertIdentical($id, $migration->Id());
-    $this->assertIdentical($label, $migration->label());
+    $this->assertEqual($id, $migration->id());
+    $this->assertEqual($label, $migration->label());
   }
 
   /**
diff --git a/core/modules/shortcut/src/Tests/ShortcutSetsTest.php b/core/modules/shortcut/src/Tests/ShortcutSetsTest.php
index bc3c5f9..47efc0f 100644
--- a/core/modules/shortcut/src/Tests/ShortcutSetsTest.php
+++ b/core/modules/shortcut/src/Tests/ShortcutSetsTest.php
@@ -73,7 +73,7 @@ function testShortcutSetEdit() {
     // Test the contents of each th cell.
     $expected_items = array(t('Name'), t('Weight'), t('Operations'));
     foreach ($elements as $key => $element) {
-      $this->assertIdentical((string) $element[0], $expected_items[$key]);
+      $this->assertEqual((string) $element[0], $expected_items[$key]);
     }
 
     // Look for test shortcuts in the table.
diff --git a/core/modules/simpletest/src/TestBase.php b/core/modules/simpletest/src/TestBase.php
index 62e4c9f..bc2b627 100644
--- a/core/modules/simpletest/src/TestBase.php
+++ b/core/modules/simpletest/src/TestBase.php
@@ -661,8 +661,7 @@ protected function assertEqual($first, $second, $message = '', $group = 'Other')
     // We cast objects implementing SafeStringInterface to string ourself so as
     // to not rely on PHP casting them to string depending on what we're
     // comparing with.
-    $this->castSafeStrings($first, $second);
-    return $this->assert($first == $second, $message ? $message : SafeMarkup::format('Value @first is equal to value @second.', array('@first' => var_export($first, TRUE), '@second' => var_export($second, TRUE))), $group);
+    return $this->assert($this->castSafeStrings($first) == $this->castSafeStrings($second), $message ? $message : SafeMarkup::format('Value @first is equal to value @second.', array('@first' => var_export($first, TRUE), '@second' => var_export($second, TRUE))), $group);
   }
 
   /**
@@ -691,37 +690,26 @@ protected function assertNotEqual($first, $second, $message = '', $group = 'Othe
   }
 
   /**
-   * Casts SafeStringInterface objects into string in 2 compared values.
+   * Casts SafeStringInterface objects into strings.
    *
-   * @param string|array &$first
-   *   The first value to act on.
-   * @param string|array &$second
-   *   The second value to act on (optional).
+   * @param string|array $value
+   *   The value to act on.
    *
    * @return mixed
-   *   The input values, with SafeStringInterface objects casted to string.
+   *   The input value, with SafeStringInterface objects casted to string.
    */
-  protected function castSafeStrings(&$first, &$second = NULL) {
-    if ($first instanceof SafeStringInterface) {
-      $first = (string) $first;
+  protected function castSafeStrings($value) {
+    if ($value instanceof SafeStringInterface) {
+      $value = (string) $value;
     }
-    if ($second instanceof SafeStringInterface) {
-      $second = (string) $second;
-    }
-    if (is_array($first)) {
-      array_walk_recursive($first, function (&$first) {
-        if ($first instanceof SafeStringInterface) {
-          $first = (string) $first;
-        }
-      });
-    }
-    if (is_array($second)) {
-      array_walk_recursive($second, function (&$second) {
-        if ($second instanceof SafeStringInterface) {
-          $second = (string) $second;
+    if (is_array($value)) {
+      array_walk_recursive($value, function (&$item) {
+        if ($item instanceof SafeStringInterface) {
+          $item = (string) $item;
         }
       });
     }
+    return $value;
   }
 
   /**
diff --git a/core/modules/simpletest/src/WebTestBase.php b/core/modules/simpletest/src/WebTestBase.php
index fcdb00a..c890beb 100644
--- a/core/modules/simpletest/src/WebTestBase.php
+++ b/core/modules/simpletest/src/WebTestBase.php
@@ -1697,7 +1697,7 @@ protected function drupalPostForm($path, $edit, $submit, array $options = array(
       $submit = (string) $submit;
     }
     if (is_array($edit)) {
-      array_walk_recursive($edit, [$this, 'castSafeStrings']);
+      $edit = $this->castSafeStrings($edit);
     }
 
     $submit_matches = FALSE;
diff --git a/core/modules/system/src/Tests/Entity/EntityDefinitionUpdateTest.php b/core/modules/system/src/Tests/Entity/EntityDefinitionUpdateTest.php
index 1010b03..af9ccbc 100644
--- a/core/modules/system/src/Tests/Entity/EntityDefinitionUpdateTest.php
+++ b/core/modules/system/src/Tests/Entity/EntityDefinitionUpdateTest.php
@@ -107,7 +107,7 @@ public function testEntityTypeUpdateWithoutData() {
         t('Update the %entity_type entity type.', array('%entity_type' => $this->entityManager->getDefinition('entity_test_update')->getLabel())),
       ),
     );
-    $this->assertIdentical($this->entityDefinitionUpdateManager->getChangeSummary(), $expected); //, 'EntityDefinitionUpdateManager reports the expected change summary.');
+    $this->assertEqual($this->entityDefinitionUpdateManager->getChangeSummary(), $expected); //, 'EntityDefinitionUpdateManager reports the expected change summary.');
 
     // Run the update and ensure the revision table is created.
     $this->entityDefinitionUpdateManager->applyUpdates();
@@ -146,7 +146,7 @@ public function testBaseFieldCreateUpdateDeleteWithoutData() {
         t('Create the %field_name field.', array('%field_name' => t('A new base field'))),
       ),
     );
-    $this->assertIdentical($this->entityDefinitionUpdateManager->getChangeSummary(), $expected, 'EntityDefinitionUpdateManager reports the expected change summary.');
+    $this->assertEqual($this->entityDefinitionUpdateManager->getChangeSummary(), $expected, 'EntityDefinitionUpdateManager reports the expected change summary.');
     $this->entityDefinitionUpdateManager->applyUpdates();
     $this->assertTrue($this->database->schema()->fieldExists('entity_test_update', 'new_base_field'), 'Column created in shared table for new_base_field.');
 
@@ -159,7 +159,7 @@ public function testBaseFieldCreateUpdateDeleteWithoutData() {
         t('Update the %field_name field.', array('%field_name' => t('A new base field'))),
       ),
     );
-    $this->assertIdentical($this->entityDefinitionUpdateManager->getChangeSummary(), $expected, 'EntityDefinitionUpdateManager reports the expected change summary.');
+    $this->assertEqual($this->entityDefinitionUpdateManager->getChangeSummary(), $expected, 'EntityDefinitionUpdateManager reports the expected change summary.');
     $this->entityDefinitionUpdateManager->applyUpdates();
     $this->assertTrue($this->database->schema()->indexExists('entity_test_update', 'entity_test_update_field__new_base_field'), 'Index created.');
 
@@ -172,7 +172,7 @@ public function testBaseFieldCreateUpdateDeleteWithoutData() {
         t('Update the %field_name field.', array('%field_name' => t('A new base field'))),
       ),
     );
-    $this->assertIdentical($this->entityDefinitionUpdateManager->getChangeSummary(), $expected, 'EntityDefinitionUpdateManager reports the expected change summary.');
+    $this->assertEqual($this->entityDefinitionUpdateManager->getChangeSummary(), $expected, 'EntityDefinitionUpdateManager reports the expected change summary.');
     $this->entityDefinitionUpdateManager->applyUpdates();
     $this->assertFalse($this->database->schema()->indexExists('entity_test_update', 'entity_test_update_field__new_base_field'), 'Index deleted.');
 
@@ -186,7 +186,7 @@ public function testBaseFieldCreateUpdateDeleteWithoutData() {
         t('Update the %field_name field.', array('%field_name' => t('A new base field'))),
       ),
     );
-    $this->assertIdentical($this->entityDefinitionUpdateManager->getChangeSummary(), $expected, 'EntityDefinitionUpdateManager reports the expected change summary.');
+    $this->assertEqual($this->entityDefinitionUpdateManager->getChangeSummary(), $expected, 'EntityDefinitionUpdateManager reports the expected change summary.');
     $this->entityDefinitionUpdateManager->applyUpdates();
     $this->assertFalse($this->database->schema()->fieldExists('entity_test_update', 'new_base_field'), 'Original column deleted in shared table for new_base_field.');
     $this->assertTrue($this->database->schema()->fieldExists('entity_test_update', 'new_base_field__value'), 'Value column created in shared table for new_base_field.');
@@ -201,7 +201,7 @@ public function testBaseFieldCreateUpdateDeleteWithoutData() {
         t('Delete the %field_name field.', array('%field_name' => t('A new base field'))),
       ),
     );
-    $this->assertIdentical($this->entityDefinitionUpdateManager->getChangeSummary(), $expected, 'EntityDefinitionUpdateManager reports the expected change summary.');
+    $this->assertEqual($this->entityDefinitionUpdateManager->getChangeSummary(), $expected, 'EntityDefinitionUpdateManager reports the expected change summary.');
     $this->entityDefinitionUpdateManager->applyUpdates();
     $this->assertFalse($this->database->schema()->fieldExists('entity_test_update', 'new_base_field_value'), 'Value column deleted from shared table for new_base_field.');
     $this->assertFalse($this->database->schema()->fieldExists('entity_test_update', 'new_base_field_format'), 'Format column deleted from shared table for new_base_field.');
@@ -220,7 +220,7 @@ public function testBundleFieldCreateUpdateDeleteWithoutData() {
         t('Create the %field_name field.', array('%field_name' => t('A new bundle field'))),
       ),
     );
-    $this->assertIdentical($this->entityDefinitionUpdateManager->getChangeSummary(), $expected, 'EntityDefinitionUpdateManager reports the expected change summary.');
+    $this->assertEqual($this->entityDefinitionUpdateManager->getChangeSummary(), $expected, 'EntityDefinitionUpdateManager reports the expected change summary.');
     $this->entityDefinitionUpdateManager->applyUpdates();
     $this->assertTrue($this->database->schema()->tableExists('entity_test_update__new_bundle_field'), 'Dedicated table created for new_bundle_field.');
 
@@ -234,7 +234,7 @@ public function testBundleFieldCreateUpdateDeleteWithoutData() {
         t('Update the %field_name field.', array('%field_name' => t('A new bundle field'))),
       ),
     );
-    $this->assertIdentical($this->entityDefinitionUpdateManager->getChangeSummary(), $expected, 'EntityDefinitionUpdateManager reports the expected change summary.');
+    $this->assertEqual($this->entityDefinitionUpdateManager->getChangeSummary(), $expected, 'EntityDefinitionUpdateManager reports the expected change summary.');
     $this->entityDefinitionUpdateManager->applyUpdates();
     $this->assertTrue($this->database->schema()->fieldExists('entity_test_update__new_bundle_field', 'new_bundle_field_format'), 'Format column created in dedicated table for new_base_field.');
 
@@ -247,7 +247,7 @@ public function testBundleFieldCreateUpdateDeleteWithoutData() {
         t('Delete the %field_name field.', array('%field_name' => t('A new bundle field'))),
       ),
     );
-    $this->assertIdentical($this->entityDefinitionUpdateManager->getChangeSummary(), $expected, 'EntityDefinitionUpdateManager reports the expected change summary.');
+    $this->assertEqual($this->entityDefinitionUpdateManager->getChangeSummary(), $expected, 'EntityDefinitionUpdateManager reports the expected change summary.');
     $this->entityDefinitionUpdateManager->applyUpdates();
     $this->assertFalse($this->database->schema()->tableExists('entity_test_update__new_bundle_field'), 'Dedicated table deleted for new_bundle_field.');
   }
@@ -489,7 +489,7 @@ public function testEntityIndexCreateDeleteWithoutData() {
         t('Update the %entity_type entity type.', array('%entity_type' => $this->entityManager->getDefinition('entity_test_update')->getLabel())),
       ),
     );
-    $this->assertIdentical($this->entityDefinitionUpdateManager->getChangeSummary(), $expected, 'EntityDefinitionUpdateManager reports the expected change summary.');
+    $this->assertEqual($this->entityDefinitionUpdateManager->getChangeSummary(), $expected, 'EntityDefinitionUpdateManager reports the expected change summary.');
 
     // Run the update and ensure the new index is created.
     $this->entityDefinitionUpdateManager->applyUpdates();
@@ -504,7 +504,7 @@ public function testEntityIndexCreateDeleteWithoutData() {
         t('Update the %entity_type entity type.', array('%entity_type' => $this->entityManager->getDefinition('entity_test_update')->getLabel())),
       ),
     );
-    $this->assertIdentical($this->entityDefinitionUpdateManager->getChangeSummary(), $expected, 'EntityDefinitionUpdateManager reports the expected change summary.');
+    $this->assertEqual($this->entityDefinitionUpdateManager->getChangeSummary(), $expected, 'EntityDefinitionUpdateManager reports the expected change summary.');
 
     // Run the update and ensure the index is deleted.
     $this->entityDefinitionUpdateManager->applyUpdates();
diff --git a/core/modules/system/src/Tests/Form/ValidationTest.php b/core/modules/system/src/Tests/Form/ValidationTest.php
index 693d0af..74e9583 100644
--- a/core/modules/system/src/Tests/Form/ValidationTest.php
+++ b/core/modules/system/src/Tests/Form/ValidationTest.php
@@ -293,7 +293,7 @@ protected function assertErrorMessages($messages) {
         $this->fail(format_string('The error message for the "@title" element with key "@key" was not found.', ['@title' => $message['title'], '@key' => $message['key']]));
       }
       else {
-        $this->assertIdentical($message['message'], (string) $element[$delta]);
+        $this->assertEqual($message['message'], (string) $element[$delta]);
       }
 
       // Gather the element for checking the jump link section.
diff --git a/core/modules/views/src/Tests/ModuleTest.php b/core/modules/views/src/Tests/ModuleTest.php
index 7d5a31b..dca3eed 100644
--- a/core/modules/views/src/Tests/ModuleTest.php
+++ b/core/modules/views/src/Tests/ModuleTest.php
@@ -178,14 +178,14 @@ public function testLoadFunctions() {
     foreach ($all_views as $id => $view) {
       $expected_options[$id] = $view->label();
     }
-    $this->assertIdentical($expected_options, Views::getViewsAsOptions(TRUE), 'Expected options array was returned.');
+    $this->assertIdentical($expected_options, $this->castSafeStrings(Views::getViewsAsOptions(TRUE)), 'Expected options array was returned.');
 
     // Test the default.
-    $this->assertIdentical($this->formatViewOptions($all_views), Views::getViewsAsOptions(), 'Expected options array for all views was returned.');
+    $this->assertIdentical($this->formatViewOptions($all_views), $this->castSafeStrings(Views::getViewsAsOptions()), 'Expected options array for all views was returned.');
     // Test enabled views.
-    $this->assertIdentical($this->formatViewOptions($expected_enabled), Views::getViewsAsOptions(FALSE, 'enabled'), 'Expected enabled options array was returned.');
+    $this->assertIdentical($this->formatViewOptions($expected_enabled), $this->castSafeStrings(Views::getViewsAsOptions(FALSE, 'enabled')), 'Expected enabled options array was returned.');
     // Test disabled views.
-    $this->assertIdentical($this->formatViewOptions($expected_disabled), Views::getViewsAsOptions(FALSE, 'disabled'), 'Expected disabled options array was returned.');
+    $this->assertIdentical($this->formatViewOptions($expected_disabled), $this->castSafeStrings(Views::getViewsAsOptions(FALSE, 'disabled')), 'Expected disabled options array was returned.');
 
     // Test the sort parameter.
     $all_views_sorted = $all_views;
@@ -201,10 +201,10 @@ public function testLoadFunctions() {
     $expected_opt_groups = array();
     foreach ($all_views as $view) {
       foreach ($view->get('display') as $display) {
-          $expected_opt_groups[$view->id()][$view->id() . ':' . $display['id']] = t('@view : @display', array('@view' => $view->id(), '@display' => $display['id']));
+          $expected_opt_groups[$view->id()][$view->id() . ':' . $display['id']] = (string) t('@view : @display', array('@view' => $view->id(), '@display' => $display['id']));
       }
     }
-    $this->assertIdentical($expected_opt_groups, Views::getViewsAsOptions(FALSE, 'all', NULL, TRUE), 'Expected option array for an option group returned.');
+    $this->assertIdentical($expected_opt_groups, $this->castSafeStrings(Views::getViewsAsOptions(FALSE, 'all', NULL, TRUE)), 'Expected option array for an option group returned.');
   }
 
   /**
@@ -347,7 +347,7 @@ protected function formatViewOptions(array $views = array()) {
     $expected_options = array();
     foreach ($views as $view) {
       foreach ($view->get('display') as $display) {
-        $expected_options[$view->id() . ':' . $display['id']] = t('View: @view - Display: @display',
+        $expected_options[$view->id() . ':' . $display['id']] = (string) t('View: @view - Display: @display',
           array('@view' => $view->id(), '@display' => $display['id']));
       }
     }
