diff --git a/core/modules/block/src/Tests/BlockInterfaceTest.php b/core/modules/block/src/Tests/BlockInterfaceTest.php
index 1464e1b..a887e89 100644
--- a/core/modules/block/src/Tests/BlockInterfaceTest.php
+++ b/core/modules/block/src/Tests/BlockInterfaceTest.php
@@ -115,10 +115,10 @@ public function testBlockInterface() {
       '#children' => 'My custom display message.',
     );
     // Ensure the build array is proper.
-    $this->assertIdenticalWithSafeStrings($display_block->build(), $expected_build, 'The plugin returned the appropriate build array.');
+    $this->assertIdentical($display_block->build(), $expected_build, 'The plugin returned the appropriate build array.');
 
     // Ensure the machine name suggestion is correct. In truth, this is actually
     // testing BlockBase's implementation, not the interface itself.
-    $this->assertIdenticalWithSafeStrings($display_block->getMachineNameSuggestion(), 'displaymessage', 'The plugin returned the expected machine name suggestion.');
+    $this->assertIdentical($display_block->getMachineNameSuggestion(), 'displaymessage', 'The plugin returned the expected machine name suggestion.');
   }
 }
diff --git a/core/modules/locale/src/Tests/LocaleImportFunctionalTest.php b/core/modules/locale/src/Tests/LocaleImportFunctionalTest.php
index 05af294..02e364b 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/system/src/Tests/Common/FormatDateTest.php b/core/modules/system/src/Tests/Common/FormatDateTest.php
index aa357dd..0ece458 100644
--- a/core/modules/system/src/Tests/Common/FormatDateTest.php
+++ b/core/modules/system/src/Tests/Common/FormatDateTest.php
@@ -88,10 +88,10 @@ function testAdminDefinedFormatDate() {
   function testFormatDate() {
     $timestamp = strtotime('2007-03-26T00:00:00+00:00');
     $this->assertIdentical(format_date($timestamp, 'custom', 'l, d-M-y H:i:s T', 'America/Los_Angeles', 'en'), 'Sunday, 25-Mar-07 17:00:00 PDT', 'Test all parameters.');
-    $this->assertIdenticalWithSafeStrings(format_date($timestamp, 'custom', 'l, d-M-y H:i:s T', 'America/Los_Angeles', self::LANGCODE), 'domingo, 25-Mar-07 17:00:00 PDT', 'Test translated format.');
-    $this->assertIdenticalWithSafeStrings(format_date($timestamp, 'custom', '\\l, d-M-y H:i:s T', 'America/Los_Angeles', self::LANGCODE), 'l, 25-Mar-07 17:00:00 PDT', 'Test an escaped format string.');
-    $this->assertIdenticalWithSafeStrings(format_date($timestamp, 'custom', '\\\\l, d-M-y H:i:s T', 'America/Los_Angeles', self::LANGCODE), '\\domingo, 25-Mar-07 17:00:00 PDT', 'Test format containing backslash character.');
-    $this->assertIdenticalWithSafeStrings(format_date($timestamp, 'custom', '\\\\\\l, d-M-y H:i:s T', 'America/Los_Angeles', self::LANGCODE), '\\l, 25-Mar-07 17:00:00 PDT', 'Test format containing backslash followed by escaped format string.');
+    $this->assertIdentical(format_date($timestamp, 'custom', 'l, d-M-y H:i:s T', 'America/Los_Angeles', self::LANGCODE), 'domingo, 25-Mar-07 17:00:00 PDT', 'Test translated format.');
+    $this->assertIdentical(format_date($timestamp, 'custom', '\\l, d-M-y H:i:s T', 'America/Los_Angeles', self::LANGCODE), 'l, 25-Mar-07 17:00:00 PDT', 'Test an escaped format string.');
+    $this->assertIdentical(format_date($timestamp, 'custom', '\\\\l, d-M-y H:i:s T', 'America/Los_Angeles', self::LANGCODE), '\\domingo, 25-Mar-07 17:00:00 PDT', 'Test format containing backslash character.');
+    $this->assertIdentical(format_date($timestamp, 'custom', '\\\\\\l, d-M-y H:i:s T', 'America/Los_Angeles', self::LANGCODE), '\\l, 25-Mar-07 17:00:00 PDT', 'Test format containing backslash followed by escaped format string.');
     $this->assertIdentical(format_date($timestamp, 'custom', 'l, d-M-y H:i:s T', 'Europe/London', 'en'), 'Monday, 26-Mar-07 01:00:00 BST', 'Test a different time zone.');
 
     // Change the default language and timezone.
diff --git a/core/modules/system/src/Tests/Entity/EntityDefinitionUpdateTest.php b/core/modules/system/src/Tests/Entity/EntityDefinitionUpdateTest.php
index 7ad44eb..43b8d24 100644
--- a/core/modules/system/src/Tests/Entity/EntityDefinitionUpdateTest.php
+++ b/core/modules/system/src/Tests/Entity/EntityDefinitionUpdateTest.php
@@ -274,7 +274,7 @@ public function testBaseFieldCreateDeleteWithExistingEntities() {
     $schema_handler = $this->database->schema();
     $this->assertTrue($schema_handler->fieldExists('entity_test_update', 'new_base_field'), 'Column created in shared table for new_base_field.');
     $entity = $this->entityManager->getStorage('entity_test_update')->load($entity->id());
-    $this->assertIdenticalWithSafeStrings($entity->name->value, $name, 'Entity data preserved during field creation.');
+    $this->assertIdentical($entity->name->value, $name, 'Entity data preserved during field creation.');
 
     // Remove the base field and run the update. Ensure the base field's column
     // is deleted and the prior saved entity data is still there.
@@ -282,7 +282,7 @@ public function testBaseFieldCreateDeleteWithExistingEntities() {
     $this->entityDefinitionUpdateManager->applyUpdates();
     $this->assertFalse($schema_handler->fieldExists('entity_test_update', 'new_base_field'), 'Column deleted from shared table for new_base_field.');
     $entity = $this->entityManager->getStorage('entity_test_update')->load($entity->id());
-    $this->assertIdenticalWithSafeStrings($entity->name->value, $name, 'Entity data preserved during field deletion.');
+    $this->assertIdentical($entity->name->value, $name, 'Entity data preserved during field deletion.');
 
     // Add a base field with a required property and run the update. Ensure
     // 'not null' is not applied and thus no exception is thrown.
@@ -331,7 +331,7 @@ public function testBundleFieldCreateDeleteWithExistingEntities() {
     $schema_handler = $this->database->schema();
     $this->assertTrue($schema_handler->tableExists('entity_test_update__new_bundle_field'), 'Dedicated table created for new_bundle_field.');
     $entity = $this->entityManager->getStorage('entity_test_update')->load($entity->id());
-    $this->assertIdenticalWithSafeStrings($entity->name->value, $name, 'Entity data preserved during field creation.');
+    $this->assertIdentical($entity->name->value, $name, 'Entity data preserved during field creation.');
 
     // Remove the base field and run the update. Ensure the bundle field's
     // table is deleted and the prior saved entity data is still there.
@@ -339,7 +339,7 @@ public function testBundleFieldCreateDeleteWithExistingEntities() {
     $this->entityDefinitionUpdateManager->applyUpdates();
     $this->assertFalse($schema_handler->tableExists('entity_test_update__new_bundle_field'), 'Dedicated table deleted for new_bundle_field.');
     $entity = $this->entityManager->getStorage('entity_test_update')->load($entity->id());
-    $this->assertIdenticalWithSafeStrings($entity->name->value, $name, 'Entity data preserved during field deletion.');
+    $this->assertIdentical($entity->name->value, $name, 'Entity data preserved during field deletion.');
 
     // Test that required columns are created as 'not null'.
     $this->addBundleField('shape_required');