diff --git a/core/modules/field/lib/Drupal/field/Tests/CrudTest.php b/core/modules/field/lib/Drupal/field/Tests/CrudTest.php
index 5ca210c..4e7557e 100644
--- a/core/modules/field/lib/Drupal/field/Tests/CrudTest.php
+++ b/core/modules/field/lib/Drupal/field/Tests/CrudTest.php
@@ -461,7 +461,7 @@ function _testActiveHelper($field_definition, $modules) {
     // while some modules remain disabled.
     while ($modules) {
       $field = field_read_field($field_name);
-      $this->assertTrue(empty($field), t('%modules disabled. The field is marked inactive.', array('%modules' => implode(', ', $modules))));
+      $this->assertTrue(empty($field), format_string('%modules disabled. The field is marked inactive.', array('%modules' => implode(', ', $modules))));
 
       $module = array_shift($modules);
       module_enable(array($module), FALSE);
diff --git a/core/modules/field/lib/Drupal/field/Tests/DisplayApiTest.php b/core/modules/field/lib/Drupal/field/Tests/DisplayApiTest.php
index fdf5e88..1c8f166 100644
--- a/core/modules/field/lib/Drupal/field/Tests/DisplayApiTest.php
+++ b/core/modules/field/lib/Drupal/field/Tests/DisplayApiTest.php
@@ -79,7 +79,7 @@ function testFieldViewField() {
     $setting = $settings['test_formatter_setting'];
     $this->assertText($this->label, 'Label was displayed.');
     foreach ($this->values as $delta => $value) {
-      $this->assertText($setting . '|' . $value['value'], t('Value @delta was displayed with expected setting.', array('@delta' => $delta)));
+      $this->assertText($setting . '|' . $value['value'], format_string('Value @delta was displayed with expected setting.', array('@delta' => $delta)));
     }
 
     // Check that explicit display settings are used.
@@ -117,7 +117,7 @@ function testFieldViewField() {
     $this->assertNoText($this->label, 'Label was not displayed.');
     $this->assertNoText('field_test_field_attach_view_alter', 'Alter not fired.');
     foreach ($this->values as $delta => $value) {
-      $this->assertText($setting . '|' . $value['value'] . '|' . ($value['value'] + 1), t('Value @delta was displayed with expected setting.', array('@delta' => $delta)));
+      $this->assertText($setting . '|' . $value['value'] . '|' . ($value['value'] + 1), format_string('Value @delta was displayed with expected setting.', array('@delta' => $delta)));
     }
 
     // View mode: check that display settings specified in the instance are
@@ -127,7 +127,7 @@ function testFieldViewField() {
     $setting = $this->instance['display']['teaser']['settings']['test_formatter_setting'];
     $this->assertText($this->label, 'Label was displayed.');
     foreach ($this->values as $delta => $value) {
-      $this->assertText($setting . '|' . $value['value'], t('Value @delta was displayed with expected setting.', array('@delta' => $delta)));
+      $this->assertText($setting . '|' . $value['value'], format_string('Value @delta was displayed with expected setting.', array('@delta' => $delta)));
     }
 
     // Unknown view mode: check that display settings for 'default' view mode
@@ -137,7 +137,7 @@ function testFieldViewField() {
     $setting = $this->instance['display']['default']['settings']['test_formatter_setting'];
     $this->assertText($this->label, 'Label was displayed.');
     foreach ($this->values as $delta => $value) {
-      $this->assertText($setting . '|' . $value['value'], t('Value @delta was displayed with expected setting.', array('@delta' => $delta)));
+      $this->assertText($setting . '|' . $value['value'], format_string('Value @delta was displayed with expected setting.', array('@delta' => $delta)));
     }
   }
 
@@ -152,7 +152,7 @@ function testFieldViewValue() {
       $item = $this->entity->{$this->field_name}[LANGUAGE_NOT_SPECIFIED][$delta];
       $output = field_view_value('test_entity', $this->entity, $this->field_name, $item);
       $this->drupalSetContent(drupal_render($output));
-      $this->assertText($setting . '|' . $value['value'], t('Value @delta was displayed with expected setting.', array('@delta' => $delta)));
+      $this->assertText($setting . '|' . $value['value'], format_string('Value @delta was displayed with expected setting.', array('@delta' => $delta)));
     }
 
     // Check that explicit display settings are used.
@@ -168,7 +168,7 @@ function testFieldViewValue() {
       $item = $this->entity->{$this->field_name}[LANGUAGE_NOT_SPECIFIED][$delta];
       $output = field_view_value('test_entity', $this->entity, $this->field_name, $item, $display);
       $this->drupalSetContent(drupal_render($output));
-      $this->assertText($setting . '|0:' . $value['value'], t('Value @delta was displayed with expected setting.', array('@delta' => $delta)));
+      $this->assertText($setting . '|0:' . $value['value'], format_string('Value @delta was displayed with expected setting.', array('@delta' => $delta)));
     }
 
     // Check that prepare_view steps are invoked.
@@ -184,7 +184,7 @@ function testFieldViewValue() {
       $item = $this->entity->{$this->field_name}[LANGUAGE_NOT_SPECIFIED][$delta];
       $output = field_view_value('test_entity', $this->entity, $this->field_name, $item, $display);
       $this->drupalSetContent(drupal_render($output));
-      $this->assertText($setting . '|' . $value['value'] . '|' . ($value['value'] + 1), t('Value @delta was displayed with expected setting.', array('@delta' => $delta)));
+      $this->assertText($setting . '|' . $value['value'] . '|' . ($value['value'] + 1), format_string('Value @delta was displayed with expected setting.', array('@delta' => $delta)));
     }
 
     // View mode: check that display settings specified in the instance are
@@ -194,7 +194,7 @@ function testFieldViewValue() {
       $item = $this->entity->{$this->field_name}[LANGUAGE_NOT_SPECIFIED][$delta];
       $output = field_view_value('test_entity', $this->entity, $this->field_name, $item, 'teaser');
       $this->drupalSetContent(drupal_render($output));
-      $this->assertText($setting . '|' . $value['value'], t('Value @delta was displayed with expected setting.', array('@delta' => $delta)));
+      $this->assertText($setting . '|' . $value['value'], format_string('Value @delta was displayed with expected setting.', array('@delta' => $delta)));
     }
 
     // Unknown view mode: check that display settings for 'default' view mode
@@ -204,7 +204,7 @@ function testFieldViewValue() {
       $item = $this->entity->{$this->field_name}[LANGUAGE_NOT_SPECIFIED][$delta];
       $output = field_view_value('test_entity', $this->entity, $this->field_name, $item, 'unknown_view_mode');
       $this->drupalSetContent(drupal_render($output));
-      $this->assertText($setting . '|' . $value['value'], t('Value @delta was displayed with expected setting.', array('@delta' => $delta)));
+      $this->assertText($setting . '|' . $value['value'], format_string('Value @delta was displayed with expected setting.', array('@delta' => $delta)));
     }
   }
 }
diff --git a/core/modules/field/lib/Drupal/field/Tests/FieldAttachOtherTest.php b/core/modules/field/lib/Drupal/field/Tests/FieldAttachOtherTest.php
index 9bf4b2e..581d1c1 100644
--- a/core/modules/field/lib/Drupal/field/Tests/FieldAttachOtherTest.php
+++ b/core/modules/field/lib/Drupal/field/Tests/FieldAttachOtherTest.php
@@ -143,7 +143,7 @@ function testFieldAttachView() {
         break;
       }
     }
-    $this->assertTrue($result, t('Variable $@field_name correctly populated.', array('@field_name' => $this->field_name)));
+    $this->assertTrue($result, format_string('Variable $@field_name correctly populated.', array('@field_name' => $this->field_name)));
   }
 
   /**
diff --git a/core/modules/field/lib/Drupal/field/Tests/FieldAttachStorageTest.php b/core/modules/field/lib/Drupal/field/Tests/FieldAttachStorageTest.php
index 501d001..690768e 100644
--- a/core/modules/field/lib/Drupal/field/Tests/FieldAttachStorageTest.php
+++ b/core/modules/field/lib/Drupal/field/Tests/FieldAttachStorageTest.php
@@ -65,9 +65,9 @@ function testFieldAttachSaveLoad() {
     $this->assertEqual(count($entity->{$this->field_name}[$langcode]), $this->field['cardinality'], 'Current revision: expected number of values');
     for ($delta = 0; $delta < $this->field['cardinality']; $delta++) {
       // The field value loaded matches the one inserted or updated.
-      $this->assertEqual($entity->{$this->field_name}[$langcode][$delta]['value'] , $values[$current_revision][$delta]['value'], t('Current revision: expected value %delta was found.', array('%delta' => $delta)));
+      $this->assertEqual($entity->{$this->field_name}[$langcode][$delta]['value'] , $values[$current_revision][$delta]['value'], format_string('Current revision: expected value %delta was found.', array('%delta' => $delta)));
       // The value added in hook_field_load() is found.
-      $this->assertEqual($entity->{$this->field_name}[$langcode][$delta]['additional_key'], 'additional_value', t('Current revision: extra information for value %delta was found', array('%delta' => $delta)));
+      $this->assertEqual($entity->{$this->field_name}[$langcode][$delta]['additional_key'], 'additional_value', format_string('Current revision: extra information for value %delta was found', array('%delta' => $delta)));
     }
 
     // Confirm each revision loads the correct data.
@@ -75,12 +75,12 @@ function testFieldAttachSaveLoad() {
       $entity = field_test_create_entity(0, $revision_id, $this->instance['bundle']);
       field_attach_load_revision($entity_type, array(0 => $entity));
       // Number of values per field loaded equals the field cardinality.
-      $this->assertEqual(count($entity->{$this->field_name}[$langcode]), $this->field['cardinality'], t('Revision %revision_id: expected number of values.', array('%revision_id' => $revision_id)));
+      $this->assertEqual(count($entity->{$this->field_name}[$langcode]), $this->field['cardinality'], format_string('Revision %revision_id: expected number of values.', array('%revision_id' => $revision_id)));
       for ($delta = 0; $delta < $this->field['cardinality']; $delta++) {
         // The field value loaded matches the one inserted or updated.
-        $this->assertEqual($entity->{$this->field_name}[$langcode][$delta]['value'], $values[$revision_id][$delta]['value'], t('Revision %revision_id: expected value %delta was found.', array('%revision_id' => $revision_id, '%delta' => $delta)));
+        $this->assertEqual($entity->{$this->field_name}[$langcode][$delta]['value'], $values[$revision_id][$delta]['value'], format_string('Revision %revision_id: expected value %delta was found.', array('%revision_id' => $revision_id, '%delta' => $delta)));
         // The value added in hook_field_load() is found.
-        $this->assertEqual($entity->{$this->field_name}[$langcode][$delta]['additional_key'], 'additional_value', t('Revision %revision_id: extra information for value %delta was found', array('%revision_id' => $revision_id, '%delta' => $delta)));
+        $this->assertEqual($entity->{$this->field_name}[$langcode][$delta]['additional_key'], 'additional_value', format_string('Revision %revision_id: extra information for value %delta was found', array('%revision_id' => $revision_id, '%delta' => $delta)));
       }
     }
   }
@@ -146,19 +146,19 @@ function testFieldAttachLoadMultiple() {
       $instances = field_info_instances($entity_type, $bundles[$index]);
       foreach ($instances as $field_name => $instance) {
         // The field value loaded matches the one inserted.
-        $this->assertEqual($entity->{$field_name}[$langcode][0]['value'], $values[$index][$field_name], t('Entity %index: expected value was found.', array('%index' => $index)));
+        $this->assertEqual($entity->{$field_name}[$langcode][0]['value'], $values[$index][$field_name], format_string('Entity %index: expected value was found.', array('%index' => $index)));
         // The value added in hook_field_load() is found.
-        $this->assertEqual($entity->{$field_name}[$langcode][0]['additional_key'], 'additional_value', t('Entity %index: extra information was found', array('%index' => $index)));
+        $this->assertEqual($entity->{$field_name}[$langcode][0]['additional_key'], 'additional_value', format_string('Entity %index: extra information was found', array('%index' => $index)));
       }
     }
 
     // Check that the single-field load option works.
     $entity = field_test_create_entity(1, 1, $bundles[1]);
     field_attach_load($entity_type, array(1 => $entity), FIELD_LOAD_CURRENT, array('field_id' => $field_ids[1]));
-    $this->assertEqual($entity->{$field_names[1]}[$langcode][0]['value'], $values[1][$field_names[1]], t('Entity %index: expected value was found.', array('%index' => 1)));
-    $this->assertEqual($entity->{$field_names[1]}[$langcode][0]['additional_key'], 'additional_value', t('Entity %index: extra information was found', array('%index' => 1)));
-    $this->assert(!isset($entity->{$field_names[2]}), t('Entity %index: field %field_name is not loaded.', array('%index' => 2, '%field_name' => $field_names[2])));
-    $this->assert(!isset($entity->{$field_names[3]}), t('Entity %index: field %field_name is not loaded.', array('%index' => 3, '%field_name' => $field_names[3])));
+    $this->assertEqual($entity->{$field_names[1]}[$langcode][0]['value'], $values[1][$field_names[1]], format_string('Entity %index: expected value was found.', array('%index' => 1)));
+    $this->assertEqual($entity->{$field_names[1]}[$langcode][0]['additional_key'], 'additional_value', format_string('Entity %index: extra information was found', array('%index' => 1)));
+    $this->assert(!isset($entity->{$field_names[2]}), format_string('Entity %index: field %field_name is not loaded.', array('%index' => 2, '%field_name' => $field_names[2])));
+    $this->assert(!isset($entity->{$field_names[3]}), format_string('Entity %index: field %field_name is not loaded.', array('%index' => 3, '%field_name' => $field_names[3])));
   }
 
   /**
@@ -208,7 +208,7 @@ function testFieldAttachSaveLoadDifferentStorage() {
     $entity = clone($entity_init);
     field_attach_load($entity_type, array($entity->ftid => $entity));
     foreach ($fields as $field) {
-      $this->assertEqual($values[$field['field_name']], $entity->{$field['field_name']}[$langcode], t('%storage storage: expected values were found.', array('%storage' => $field['storage']['type'])));
+      $this->assertEqual($values[$field['field_name']], $entity->{$field['field_name']}[$langcode], format_string('%storage storage: expected values were found.', array('%storage' => $field['storage']['type'])));
     }
   }
 
@@ -249,8 +249,8 @@ function testFieldStorageDetailsAlter() {
     // Test current and revision storage details together because the columns
     // are the same.
     foreach ((array) $field['columns'] as $column_name => $attributes) {
-      $this->assertEqual($details[FIELD_LOAD_CURRENT]['moon'][$column_name], $column_name, t('Column name %value matches the definition in %bin.', array('%value' => $column_name, '%bin' => 'moon[FIELD_LOAD_CURRENT]')));
-      $this->assertEqual($details[FIELD_LOAD_REVISION]['mars'][$column_name], $column_name, t('Column name %value matches the definition in %bin.', array('%value' => $column_name, '%bin' => 'mars[FIELD_LOAD_REVISION]')));
+      $this->assertEqual($details[FIELD_LOAD_CURRENT]['moon'][$column_name], $column_name, format_string('Column name %value matches the definition in %bin.', array('%value' => $column_name, '%bin' => 'moon[FIELD_LOAD_CURRENT]')));
+      $this->assertEqual($details[FIELD_LOAD_REVISION]['mars'][$column_name], $column_name, format_string('Column name %value matches the definition in %bin.', array('%value' => $column_name, '%bin' => 'mars[FIELD_LOAD_REVISION]')));
     }
   }
 
diff --git a/core/modules/field/lib/Drupal/field/Tests/FieldInfoTest.php b/core/modules/field/lib/Drupal/field/Tests/FieldInfoTest.php
index d5e3569..30e7015 100644
--- a/core/modules/field/lib/Drupal/field/Tests/FieldInfoTest.php
+++ b/core/modules/field/lib/Drupal/field/Tests/FieldInfoTest.php
@@ -38,33 +38,33 @@ function testFieldInfo() {
     $info = field_info_field_types();
     foreach ($field_test_info as $t_key => $field_type) {
       foreach ($field_type as $key => $val) {
-        $this->assertEqual($info[$t_key][$key], $val, t("Field type $t_key key $key is $val"));
+        $this->assertEqual($info[$t_key][$key], $val, format_string('Field type %t_key key %key is %value', array('%t_key' => $t_key, '%key' => $key, '%value' => $val)));
       }
-      $this->assertEqual($info[$t_key]['module'], 'field_test',  t("Field type field_test module appears"));
+      $this->assertEqual($info[$t_key]['module'], 'field_test',  'Field type field_test module appears.');
     }
 
     $formatter_info = field_test_field_formatter_info();
     $info = field_info_formatter_types();
     foreach ($formatter_info as $f_key => $formatter) {
       foreach ($formatter as $key => $val) {
-        $this->assertEqual($info[$f_key][$key], $val, t("Formatter type $f_key key $key is $val"));
+        $this->assertEqual($info[$f_key][$key], $val, format_string('Formatter type %t_key key %key is %value', array('%t_key' => $t_key, '%key' => $key, '%value' => $val)));
       }
-      $this->assertEqual($info[$f_key]['module'], 'field_test',  t("Formatter type field_test module appears"));
+      $this->assertEqual($info[$f_key]['module'], 'field_test',  'Formatter type field_test module appears.');
     }
 
     $storage_info = field_test_field_storage_info();
     $info = field_info_storage_types();
     foreach ($storage_info as $s_key => $storage) {
       foreach ($storage as $key => $val) {
-        $this->assertEqual($info[$s_key][$key], $val, t("Storage type $s_key key $key is $val"));
+        $this->assertEqual($info[$s_key][$key], $val, format_string('Storage type %t_key key %key is %value', array('%t_key' => $t_key, '%key' => $key, '%value' => $val)));
       }
-      $this->assertEqual($info[$s_key]['module'], 'field_test',  t("Storage type field_test module appears"));
+      $this->assertEqual($info[$s_key]['module'], 'field_test',  'Storage type field_test module appears.');
     }
 
     // Verify that no unexpected instances exist.
     $instances = field_info_instances('test_entity');
     $expected = array();
-    $this->assertIdentical($instances, $expected, "field_info_instances('test_entity') returns " . var_export($expected, TRUE) . '.');
+    $this->assertIdentical($instances, $expected, format_string("field_info_instances('test_entity') returns %expected.", array('%expected' => var_export($expected, TRUE))));
     $instances = field_info_instances('test_entity', 'test_bundle');
     $this->assertIdentical($instances, array(), "field_info_instances('test_entity', 'test_bundle') returns an empty array.");
 
@@ -82,7 +82,7 @@ function testFieldInfo() {
     $this->assertEqual($fields[$field['field_name']]['module'], 'field_test', 'info fields contains field module');
     $settings = array('test_field_setting' => 'dummy test string');
     foreach ($settings as $key => $val) {
-      $this->assertEqual($fields[$field['field_name']]['settings'][$key], $val, t("Field setting $key has correct default value $val"));
+      $this->assertEqual($fields[$field['field_name']]['settings'][$key], $val, format_string('Field setting %key has correct default value %value', array('%key' => $key, '%value' => $val)));
     }
     $this->assertEqual($fields[$field['field_name']]['cardinality'], 1, 'info fields contains cardinality 1');
     $this->assertEqual($fields[$field['field_name']]['active'], 1, 'info fields contains active 1');
@@ -121,7 +121,7 @@ function testFieldInfo() {
     // Test with an entity type that has no bundles.
     $instances = field_info_instances('user');
     $expected = array();
-    $this->assertIdentical($instances, $expected, "field_info_instances('user') returns " . var_export($expected, TRUE) . '.');
+    $this->assertIdentical($instances, $expected, format_string("field_info_instances('user') returns %expected.", array('%expected' => var_export($expected, TRUE))));
     $instances = field_info_instances('user', 'user');
     $this->assertIdentical($instances, array(), "field_info_instances('user', 'user') returns an empty array.");
   }
@@ -206,9 +206,9 @@ function testInstancePrepare() {
 
     // Check that display settings are set for the 'default' mode.
     $display = $instance['display']['default'];
-    $this->assertIdentical($display['type'], $field_type['default_formatter'], t("Formatter is set for the 'default' view mode"));
+    $this->assertIdentical($display['type'], $field_type['default_formatter'], "Formatter is set for the 'default' view mode.");
     $formatter_type = field_info_formatter_types($display['type']);
-    $this->assertIdentical($display['settings'], $formatter_type['settings'] , t("Formatter settings are set for the 'default' view mode"));
+    $this->assertIdentical($display['settings'], $formatter_type['settings'] , "Formatter settings are set for the 'default' view mode.");
 
   }
 
@@ -320,18 +320,18 @@ function testSettingsInfo() {
       $info[$name]['instance_settings']['user_register_form'] = FALSE;
     }
     foreach ($info as $type => $data) {
-      $this->assertIdentical(field_info_field_settings($type), $data['settings'], "field_info_field_settings returns {$type}'s field settings");
-      $this->assertIdentical(field_info_instance_settings($type), $data['instance_settings'], "field_info_field_settings returns {$type}'s field instance settings");
+      $this->assertIdentical(field_info_field_settings($type), $data['settings'], format_string("field_info_field_settings returns {%type}'s field settings", array('%type' => $type)));
+      $this->assertIdentical(field_info_instance_settings($type), $data['instance_settings'], format_string("field_info_field_settings returns {%type}'s field instance settings", array('%type' => $type)));
     }
 
     foreach (array('test_field_widget', 'test_field_widget_multiple') as $type) {
       $info = field_info_widget_types($type);
-      $this->assertIdentical(field_info_widget_settings($type), $info['settings'], "field_info_widget_settings returns {$type}'s widget settings");
+      $this->assertIdentical(field_info_widget_settings($type), $info['settings'], format_string("field_info_widget_settings returns {%type}'s widget settings", array('%type' => $type)));
     }
 
     $info = field_test_field_formatter_info();
     foreach ($info as $type => $data) {
-      $this->assertIdentical(field_info_formatter_settings($type), $data['settings'], "field_info_formatter_settings returns {$type}'s formatter settings");
+      $this->assertIdentical(field_info_formatter_settings($type), $data['settings'], format_string("field_info_formatter_settings returns {%type}'s formatter settings", array('%type' => $type)));
     }
   }
 }
diff --git a/core/modules/field/lib/Drupal/field/Tests/FieldTestBase.php b/core/modules/field/lib/Drupal/field/Tests/FieldTestBase.php
index fc5cac0..d82165f 100644
--- a/core/modules/field/lib/Drupal/field/Tests/FieldTestBase.php
+++ b/core/modules/field/lib/Drupal/field/Tests/FieldTestBase.php
@@ -64,7 +64,7 @@ function assertFieldValues($entity, $field_name, $langcode, $expected_values, $c
     $values = isset($e->{$field_name}[$langcode]) ? $e->{$field_name}[$langcode] : array();
     $this->assertEqual(count($values), count($expected_values), 'Expected number of values were saved.');
     foreach ($expected_values as $key => $value) {
-      $this->assertEqual($values[$key][$column], $value, t('Value @value was saved correctly.', array('@value' => $value)));
+      $this->assertEqual($values[$key][$column], $value, format_string('Value @value was saved correctly.', array('@value' => $value)));
     }
   }
 }
diff --git a/core/modules/field/lib/Drupal/field/Tests/TranslationTest.php b/core/modules/field/lib/Drupal/field/Tests/TranslationTest.php
index 8e720b0..8dc0418 100644
--- a/core/modules/field/lib/Drupal/field/Tests/TranslationTest.php
+++ b/core/modules/field/lib/Drupal/field/Tests/TranslationTest.php
@@ -83,11 +83,11 @@ function testFieldAvailableLanguages() {
     $available_langcodes = field_available_languages($this->entity_type, $this->field);
     foreach ($available_langcodes as $delta => $langcode) {
       if ($langcode != 'xx' && $langcode != 'en') {
-        $this->assertTrue(in_array($langcode, $langcodes), t('%language is an enabled language.', array('%language' => $langcode)));
+        $this->assertTrue(in_array($langcode, $langcodes), format_string('%language is an enabled language.', array('%language' => $langcode)));
       }
     }
-    $this->assertTrue(in_array('xx', $available_langcodes), t('%language was made available.', array('%language' => 'xx')));
-    $this->assertFalse(in_array('en', $available_langcodes), t('%language was made unavailable.', array('%language' => 'en')));
+    $this->assertTrue(in_array('xx', $available_langcodes), format_string('%language was made available.', array('%language' => 'xx')));
+    $this->assertFalse(in_array('en', $available_langcodes), format_string('%language was made unavailable.', array('%language' => 'en')));
 
     // Test field_available_languages() behavior for untranslatable fields.
     $this->field['translatable'] = FALSE;
@@ -128,7 +128,7 @@ function testFieldInvoke() {
       $hash = hash('sha256', serialize(array($entity_type, $entity, $this->field_name, $langcode, $values[$langcode])));
       // Check whether the parameters passed to _field_invoke() were correctly
       // forwarded to the callback function.
-      $this->assertEqual($hash, $result, t('The result for %language is correctly stored.', array('%language' => $langcode)));
+      $this->assertEqual($hash, $result, format_string('The result for %language is correctly stored.', array('%language' => $langcode)));
     }
 
     $this->assertEqual(count($results), count($available_langcodes), 'No unavailable language has been processed.');
@@ -192,17 +192,17 @@ function testFieldInvokeMultiple() {
           $hash = hash('sha256', serialize(array($entity_type, $entities[$id], $this->field_name, $langcode, $values[$id][$langcode])));
           // Check whether the parameters passed to _field_invoke_multiple()
           // were correctly forwarded to the callback function.
-          $this->assertEqual($hash, $result, t('The result for entity %id/%language is correctly stored.', array('%id' => $id, '%language' => $langcode)));
+          $this->assertEqual($hash, $result, format_string('The result for entity %id/%language is correctly stored.', array('%id' => $id, '%language' => $langcode)));
         }
       }
-      $this->assertEqual(count($results), count($available_langcodes), t('No unavailable language has been processed for entity %id.', array('%id' => $id)));
+      $this->assertEqual(count($results), count($available_langcodes), format_string('No unavailable language has been processed for entity %id.', array('%id' => $id)));
     }
 
     $null = NULL;
     $grouped_results = _field_invoke_multiple('test_op_multiple', $entity_type, $entities, $null, $null, $options);
     foreach ($grouped_results as $id => $results) {
       foreach ($results as $langcode => $result) {
-        $this->assertTrue(isset($options['langcode'][$id]), t('The result language code %langcode for entity %id was correctly suggested (display language: %display_langcode).', array('%id' => $id, '%langcode' => $langcode, '%display_langcode' => $display_langcode)));
+        $this->assertTrue(isset($options['langcode'][$id]), format_string('The result language code %langcode for entity %id was correctly suggested (display language: %display_langcode).', array('%id' => $id, '%langcode' => $langcode, '%display_langcode' => $display_langcode)));
       }
     }
   }
@@ -240,7 +240,7 @@ function testTranslatableFieldSaveLoad() {
       foreach ($items as $delta => $item) {
         $result = $result && $item['value'] == $entity->{$this->field_name}[$langcode][$delta]['value'];
       }
-      $this->assertTrue($result, t('%language translation correctly handled.', array('%language' => $langcode)));
+      $this->assertTrue($result, format_string('%language translation correctly handled.', array('%language' => $langcode)));
     }
   }
 
@@ -308,7 +308,7 @@ function testFieldDisplayLanguage() {
     $display_langcodes = field_language($entity_type, $entity, NULL, $requested_langcode);
     foreach ($instances as $instance) {
       $field_name = $instance['field_name'];
-      $this->assertTrue($display_langcodes[$field_name] == $locked_languages[$field_name], t('The display language for field %field_name is %language.', array('%field_name' => $field_name, '%language' => $locked_languages[$field_name])));
+      $this->assertTrue($display_langcodes[$field_name] == $locked_languages[$field_name], format_string('The display language for field %field_name is %language.', array('%field_name' => $field_name, '%language' => $locked_languages[$field_name])));
     }
 
     // Test multiple-fields display languages for translatable entities.
@@ -321,13 +321,13 @@ function testFieldDisplayLanguage() {
       // As the requested language was not assinged to any field, if the
       // returned language is defined for the current field, core fallback rules
       // were successfully applied.
-      $this->assertTrue(isset($entity->{$field_name}[$langcode]) && $langcode != $requested_langcode, t('The display language for the field %field_name is %language.', array('%field_name' => $field_name, '%language' => $langcode)));
+      $this->assertTrue(isset($entity->{$field_name}[$langcode]) && $langcode != $requested_langcode, format_string('The display language for the field %field_name is %language.', array('%field_name' => $field_name, '%language' => $langcode)));
     }
 
     // Test single-field display language.
     drupal_static_reset('field_language');
     $langcode = field_language($entity_type, $entity, $this->field_name, $requested_langcode);
-    $this->assertTrue(isset($entity->{$this->field_name}[$langcode]) && $langcode != $requested_langcode, t('The display language for the (single) field %field_name is %language.', array('%field_name' => $field_name, '%language' => $langcode)));
+    $this->assertTrue(isset($entity->{$this->field_name}[$langcode]) && $langcode != $requested_langcode, format_string('The display language for the (single) field %field_name is %language.', array('%field_name' => $field_name, '%language' => $langcode)));
 
     // Test field_language() basic behavior without language fallback.
     variable_set('field_test_language_fallback', FALSE);
@@ -378,7 +378,7 @@ private function checkTranslationRevisions($eid, $evid, $available_langcodes) {
     $entity = field_test_entity_test_load($eid, $evid);
     foreach ($available_langcodes as $langcode => $value) {
       $passed = isset($entity->{$field_name}[$langcode]) && $entity->{$field_name}[$langcode][0]['value'] == $value + 1;
-      $this->assertTrue($passed, t('The @language translation for revision @revision was correctly stored', array('@language' => $langcode, '@revision' => $entity->ftvid)));
+      $this->assertTrue($passed, format_string('The @language translation for revision @revision was correctly stored', array('@language' => $langcode, '@revision' => $entity->ftvid)));
     }
   }
 }