diff --git a/core/modules/system/lib/Drupal/system/Tests/Bootstrap/PageCacheTest.php b/core/modules/system/lib/Drupal/system/Tests/Bootstrap/PageCacheTest.php
index d283785..0f00baf 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Bootstrap/PageCacheTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Bootstrap/PageCacheTest.php
@@ -153,7 +153,7 @@ class PageCacheTest extends WebTestBase {
     $this->drupalGet('');
     $this->assertEqual($this->drupalGetHeader('X-Drupal-Cache'), 'HIT', 'Page was cached.');
     $this->assertFalse($this->drupalGetHeader('Content-Encoding'), 'A Content-Encoding header was not sent.');
-    $this->assertTitle(t('Welcome to @site-name | @site-name', array('@site-name' => config('system.site')->get('name'))), t('Site title matches.'));
+    $this->assertTitle(t('Welcome to @site-name | @site-name', array('@site-name' => config('system.site')->get('name'))), 'Site title matches.');
     $this->assertRaw('</html>', 'Page was not compressed.');
   }
 }
diff --git a/core/modules/system/lib/Drupal/system/Tests/Bootstrap/ResettableStaticUnitTest.php b/core/modules/system/lib/Drupal/system/Tests/Bootstrap/ResettableStaticUnitTest.php
index 8024486..345c617 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Bootstrap/ResettableStaticUnitTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Bootstrap/ResettableStaticUnitTest.php
@@ -29,7 +29,7 @@ class ResettableStaticUnitTest extends UnitTestBase {
   function testDrupalStatic() {
     $name = __CLASS__ . '_' . __METHOD__;
     $var = &drupal_static($name, 'foo');
-    $this->assertEqual($var, 'foo', t('Variable returned by drupal_static() was set to its default.'));
+    $this->assertEqual($var, 'foo', 'Variable returned by drupal_static() was set to its default.');
 
     // Call the specific reset and the global reset each twice to ensure that
     // multiple resets can be issued without odd side effects.
diff --git a/core/modules/system/lib/Drupal/system/Tests/Common/HtmlIdentifierUnitTest.php b/core/modules/system/lib/Drupal/system/Tests/Common/HtmlIdentifierUnitTest.php
index 55d8b16..d0daf38 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Common/HtmlIdentifierUnitTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Common/HtmlIdentifierUnitTest.php
@@ -42,7 +42,7 @@ class HtmlIdentifierUnitTest extends UnitTestBase {
    */
   function testDrupalHTMLClass() {
     // Verify Drupal coding standards are enforced.
-    $this->assertIdentical(drupal_html_class('CLASS NAME_[Ü]'), 'class-name--ü', t('Enforce Drupal coding standards.'));
+    $this->assertIdentical(drupal_html_class('CLASS NAME_[Ü]'), 'class-name--ü', 'Enforce Drupal coding standards.');
   }
 
   /**
diff --git a/core/modules/system/lib/Drupal/system/Tests/Common/JavaScriptTest.php b/core/modules/system/lib/Drupal/system/Tests/Common/JavaScriptTest.php
index 9507e3b..21ea3de 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Common/JavaScriptTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Common/JavaScriptTest.php
@@ -195,7 +195,7 @@ class JavaScriptTest extends WebTestBase {
     drupal_add_library('system', 'drupal');
     $inline = 'jQuery(function () { });';
     $javascript = drupal_add_js($inline, array('type' => 'inline', 'scope' => 'footer'));
-    $this->assertTrue(array_key_exists('core/misc/jquery.js', $javascript), t('jQuery is added when inline scripts are added.'));
+    $this->assertTrue(array_key_exists('core/misc/jquery.js', $javascript), 'jQuery is added when inline scripts are added.');
     $data = end($javascript);
     $this->assertEqual($inline, $data['data'], 'Inline JavaScript is correctly added to the footer.');
   }
@@ -445,7 +445,7 @@ class JavaScriptTest extends WebTestBase {
    */
   function testLibraryRender() {
     $result = drupal_add_library('system', 'jquery.farbtastic');
-    $this->assertTrue($result !== FALSE, t('Library was added without errors.'));
+    $this->assertTrue($result !== FALSE, 'Library was added without errors.');
     $scripts = drupal_get_js();
     $styles = drupal_get_css();
     $this->assertTrue(strpos($scripts, 'core/misc/farbtastic/farbtastic.js'), 'JavaScript of library was added to the page.');
@@ -460,7 +460,7 @@ class JavaScriptTest extends WebTestBase {
   function testLibraryAlter() {
     // Verify that common_test altered the title of Farbtastic.
     $library = drupal_get_library('system', 'jquery.farbtastic');
-    $this->assertEqual($library['title'], 'Farbtastic: Altered Library', t('Registered libraries were altered.'));
+    $this->assertEqual($library['title'], 'Farbtastic: Altered Library', 'Registered libraries were altered.');
 
     // common_test_library_info_alter() also added a dependency on jQuery Form.
     drupal_add_library('system', 'jquery.farbtastic');
@@ -483,11 +483,11 @@ class JavaScriptTest extends WebTestBase {
    */
   function testLibraryUnknown() {
     $result = drupal_get_library('unknown', 'unknown');
-    $this->assertFalse($result, t('Unknown library returned FALSE.'));
+    $this->assertFalse($result, 'Unknown library returned FALSE.');
     drupal_static_reset('drupal_get_library');
 
     $result = drupal_add_library('unknown', 'unknown');
-    $this->assertFalse($result, t('Unknown library returned FALSE.'));
+    $this->assertFalse($result, 'Unknown library returned FALSE.');
     $scripts = drupal_get_js();
     $this->assertTrue(strpos($scripts, 'unknown') === FALSE, 'Unknown library was not added to the page.');
   }
diff --git a/core/modules/system/lib/Drupal/system/Tests/Common/JsonUnitTest.php b/core/modules/system/lib/Drupal/system/Tests/Common/JsonUnitTest.php
index 9f205e6..3e771e4 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Common/JsonUnitTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Common/JsonUnitTest.php
@@ -48,7 +48,7 @@ class JsonUnitTest extends UnitTestBase {
     $this->assertTrue(strlen($json) > strlen($str), 'A JSON encoded string is larger than the source string.');
 
     // The first and last characters should be ", and no others.
-    $this->assertTrue($json[0] == '"', t('A JSON encoded string begins with ".'));
+    $this->assertTrue($json[0] == '"', 'A JSON encoded string begins with ".');
     $this->assertTrue($json[strlen($json) - 1] == '"', 'A JSON encoded string ends with ".');
     $this->assertTrue(substr_count($json, '"') == 2, 'A JSON encoded string contains exactly two ".');
 
diff --git a/core/modules/system/lib/Drupal/system/Tests/Common/ParseInfoFileUnitTest.php b/core/modules/system/lib/Drupal/system/Tests/Common/ParseInfoFileUnitTest.php
index 0b211a2..1efd9e7 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Common/ParseInfoFileUnitTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Common/ParseInfoFileUnitTest.php
@@ -26,8 +26,8 @@ class ParseInfoFileUnitTest extends UnitTestBase {
    */
   function testParseInfoFile() {
     $info_values = drupal_parse_info_file(drupal_get_path('module', 'system') . '/tests/common_test_info.txt');
-    $this->assertEqual($info_values['simple_string'], 'A simple string', t('Simple string value was parsed correctly.'), 'System');
-    $this->assertEqual($info_values['simple_constant'], WATCHDOG_INFO, t('Constant value was parsed correctly.'), 'System');
-    $this->assertEqual($info_values['double_colon'], 'dummyClassName::', t('Value containing double-colon was parsed correctly.'), 'System');
+    $this->assertEqual($info_values['simple_string'], 'A simple string', 'Simple string value was parsed correctly.', 'System');
+    $this->assertEqual($info_values['simple_constant'], WATCHDOG_INFO, 'Constant value was parsed correctly.', 'System');
+    $this->assertEqual($info_values['double_colon'], 'dummyClassName::', 'Value containing double-colon was parsed correctly.', 'System');
   }
 }
diff --git a/core/modules/system/lib/Drupal/system/Tests/Common/RenderTest.php b/core/modules/system/lib/Drupal/system/Tests/Common/RenderTest.php
index 14241e0..7786d28 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Common/RenderTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Common/RenderTest.php
@@ -295,7 +295,7 @@ class RenderTest extends WebTestBase {
     // @see Drupal\simpletest\WebTestBase::xpath()
     $xpath = $this->buildXPathQuery($xpath, $xpath_args);
     $element += array('#value' => NULL);
-    $this->assertFieldByXPath($xpath, $element['#value'], t('#type @type was properly rendered.', array(
+    $this->assertFieldByXPath($xpath, $element['#value'], format_string('#type @type was properly rendered.', array(
       '@type' => var_export($element['#type'], TRUE),
     )));
   }
diff --git a/core/modules/system/lib/Drupal/system/Tests/Common/SimpleTestErrorCollectorTest.php b/core/modules/system/lib/Drupal/system/Tests/Common/SimpleTestErrorCollectorTest.php
index 6e41753..f37cb97 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Common/SimpleTestErrorCollectorTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Common/SimpleTestErrorCollectorTest.php
@@ -45,7 +45,7 @@ class SimpleTestErrorCollectorTest extends WebTestBase {
   function testErrorCollect() {
     $this->collectedErrors = array();
     $this->drupalGet('error-test/generate-warnings-with-report');
-    $this->assertEqual(count($this->collectedErrors), 3, t('Three errors were collected'));
+    $this->assertEqual(count($this->collectedErrors), 3, 'Three errors were collected');
 
     if (count($this->collectedErrors) == 3) {
       $this->assertError($this->collectedErrors[0], 'Notice', 'error_test_generate_warnings()', 'error_test.module', 'Undefined variable: bananas');