diff --git a/core/lib/Drupal/Core/Config/Schema/SchemaCheckTrait.php b/core/lib/Drupal/Core/Config/Schema/SchemaCheckTrait.php
index 0fccd47..5127adc 100644
--- a/core/lib/Drupal/Core/Config/Schema/SchemaCheckTrait.php
+++ b/core/lib/Drupal/Core/Config/Schema/SchemaCheckTrait.php
@@ -81,7 +81,7 @@ protected function checkValue($key, $value) {
     $error_key = $this->configName . ':' . $key;
     $element = $this->schema->get($key);
     if ($element instanceof Undefined) {
-      return array($error_key => 'Missing schema.');
+      return array($error_key => 'missing schema');
     }
 
     // Do not check value if it is defined to be ignored.
@@ -104,13 +104,13 @@ protected function checkValue($key, $value) {
       }
       $class = get_class($element);
       if (!$success) {
-        return array($error_key => "Variable type is $type but applied schema class is $class.");
+        return array($error_key => "variable type is $type but applied schema class is $class");
       }
     }
     else {
       $errors = array();
       if (!$element instanceof TraversableTypedDataInterface) {
-        $errors[$error_key] = 'Non-scalar value but not defined as an array (such as mapping or sequence).';
+        $errors[$error_key] = 'non-scalar value but not defined as an array (such as mapping or sequence)';
       }
 
       // Go on processing so we can get errors on all levels. Any non-scalar
diff --git a/core/lib/Drupal/Core/Config/Testing/ConfigSchemaChecker.php b/core/lib/Drupal/Core/Config/Testing/ConfigSchemaChecker.php
index 421071b..db80944 100644
--- a/core/lib/Drupal/Core/Config/Testing/ConfigSchemaChecker.php
+++ b/core/lib/Drupal/Core/Config/Testing/ConfigSchemaChecker.php
@@ -55,7 +55,7 @@ public function __construct(TypedConfigManagerInterface $typed_manager) {
   /**
    * Checks that configuration complies with its schema on config save.
    *
-   * @param ConfigCrudEvent $event
+   * @param \Drupal\Core\Config\ConfigCrudEvent $event
    *   The configuration event.
    *
    * @throws \Drupal\Core\Config\Schema\SchemaIncompleteException
@@ -75,7 +75,7 @@ public function onConfigSave(ConfigCrudEvent $event) {
       elseif (is_array($errors)) {
         $text_errors = [];
         foreach ($errors as $key => $error) {
-          $text_errors[] = String::format('@key: @error', array('@key' => $key, '@error' => $error));
+          $text_errors[] = String::format('@key @error', array('@key' => $key, '@error' => $error));
         }
         throw new SchemaIncompleteException(String::format('Schema errors for @config_name with the following errors: @errors', array('@config_name' => $name, '@errors' => implode(', ', $text_errors))));
       }
diff --git a/core/modules/config/src/Tests/SchemaCheckTestTrait.php b/core/modules/config/src/Tests/SchemaCheckTestTrait.php
index c5b4cba..3a88296 100644
--- a/core/modules/config/src/Tests/SchemaCheckTestTrait.php
+++ b/core/modules/config/src/Tests/SchemaCheckTestTrait.php
@@ -45,7 +45,7 @@ public function assertConfigSchema(TypedConfigManagerInterface $typed_config, $c
       foreach ($errors as $key => $error) {
         // @todo Since the use of this trait is under TestBase, it works.
         //  Can be fixed as part of https://drupal.org/node/2260053.
-        $this->fail($key . ': ' . $error);
+        $this->fail(String::format('Schema key @key failed with: @error', array('@key' => $key, '@error' => $error)));
       }
     }
   }
diff --git a/core/modules/config/src/Tests/SchemaCheckTraitTest.php b/core/modules/config/src/Tests/SchemaCheckTraitTest.php
index 890eed8..450d4f1 100644
--- a/core/modules/config/src/Tests/SchemaCheckTraitTest.php
+++ b/core/modules/config/src/Tests/SchemaCheckTraitTest.php
@@ -61,9 +61,9 @@ public function testTrait() {
     $config_data['boolean'] = array();
     $ret = $this->checkConfigSchema($this->typedConfig, 'config_test.types', $config_data);
     $expected = array(
-      'config_test.types:new_key' => 'Missing schema.',
-      'config_test.types:new_array' => 'Missing schema.',
-      'config_test.types:boolean' => 'Non-scalar value but not defined as an array (such as mapping or sequence).',
+      'config_test.types:new_key' => 'missing schema',
+      'config_test.types:new_array' => 'missing schema',
+      'config_test.types:boolean' => 'non-scalar value but not defined as an array (such as mapping or sequence)',
     );
     $this->assertIdentical($ret, $expected);
   }
diff --git a/core/modules/config/src/Tests/SchemaConfigListenerTest.php b/core/modules/config/src/Tests/SchemaConfigListenerTest.php
index 4796547..84bf60e 100644
--- a/core/modules/config/src/Tests/SchemaConfigListenerTest.php
+++ b/core/modules/config/src/Tests/SchemaConfigListenerTest.php
@@ -32,40 +32,40 @@ class SchemaConfigListenerTest extends KernelTestBase {
    * Tests \Drupal\Core\Config\Testing\ConfigSchemaChecker.
    */
   public function testConfigSchemaChecker() {
-    // Test a non existing schema.
-    $msg = 'Expected SchemaIncompleteException thrown';
+    // Test a non-existing schema.
+    $message = 'Expected SchemaIncompleteException thrown';
     try {
       \Drupal::config('config_schema_test.noschema')->set('foo', 'bar')->save();
-      $this->fail($msg);
+      $this->fail($message);
     }
     catch (SchemaIncompleteException $e) {
-      $this->pass($msg);
+      $this->pass($message);
       $this->assertEqual('No schema for config_schema_test.noschema', $e->getMessage());
     }
 
     // Test a valid schema.
-    $msg = 'Unexpected SchemaIncompleteException thrown';
+    $message = 'Unexpected SchemaIncompleteException thrown';
     $config = \Drupal::config('config_test.types')->set('int', 10);
     try {
       $config->save();
-      $this->pass($msg);
+      $this->pass($message);
     }
     catch (SchemaIncompleteException $e) {
-      $this->fail($msg);
+      $this->fail($message);
     }
 
     // Test an invalid schema.
-    $msg = 'Expected SchemaIncompleteException thrown';
+    $message = 'Expected SchemaIncompleteException thrown';
     $config = \Drupal::config('config_test.types')
       ->set('foo', 'bar')
       ->set('array', 1);
     try {
       $config->save();
-      $this->fail($msg);
+      $this->fail($message);
     }
     catch (SchemaIncompleteException $e) {
-      $this->pass($msg);
-      $this->pass('Schema errors for config_test.types with the following errors: config_test.types:foo: Missing schema., config_test.types:array: Variable type is integer but applied schema class is Drupal\Core\Config\Schema\Sequence.');
+      $this->pass($message);
+      $this->assertEqual('Schema errors for config_test.types with the following errors: config_test.types:foo missing schema, config_test.types:array variable type is integer but applied schema class is Drupal\Core\Config\Schema\Sequence', $e->getMessage());
     }
   }
 
diff --git a/core/modules/config/src/Tests/SchemaConfigListenerWebTest.php b/core/modules/config/src/Tests/SchemaConfigListenerWebTest.php
index 86e28d9..10ddc7b 100644
--- a/core/modules/config/src/Tests/SchemaConfigListenerWebTest.php
+++ b/core/modules/config/src/Tests/SchemaConfigListenerWebTest.php
@@ -33,7 +33,7 @@ class SchemaConfigListenerWebTest extends WebTestBase {
    * Tests \Drupal\Core\Config\Testing\ConfigSchemaChecker.
    */
   public function testConfigSchemaChecker() {
-    // Test a non existing schema.
+    // Test a non-existing schema.
     $msg = 'Expected SchemaIncompleteException thrown';
     try {
       \Drupal::config('config_schema_test.noschema')->set('foo', 'bar')->save();
@@ -66,7 +66,7 @@ public function testConfigSchemaChecker() {
     }
     catch (SchemaIncompleteException $e) {
       $this->pass($msg);
-      $this->pass('Schema errors for config_test.types with the following errors: config_test.types:foo: Missing schema., config_test.types:array: Variable type is integer but applied schema class is Drupal\Core\Config\Schema\Sequence.');
+      $this->assertEqual('Schema errors for config_test.types with the following errors: config_test.types:array variable type is integer but applied schema class is Drupal\Core\Config\Schema\Sequence, config_test.types:foo missing schema', $e->getMessage());
     }
 
     // Test that the config event listener is working in the child site.
diff --git a/core/modules/system/src/Tests/Menu/MenuTreeStorageTest.php b/core/modules/system/src/Tests/Menu/MenuTreeStorageTest.php
index a923e9b..39c403c 100644
--- a/core/modules/system/src/Tests/Menu/MenuTreeStorageTest.php
+++ b/core/modules/system/src/Tests/Menu/MenuTreeStorageTest.php
@@ -307,15 +307,15 @@ public function testLoadByProperties() {
       array('foo' => 'bar'),
       array(0 => 'wrong'),
     );
-    $msg = 'An invalid property name throws an exception.';
+    $message = 'An invalid property name throws an exception.';
     foreach ($tests as $properties) {
       try {
         $this->treeStorage->loadByProperties($properties);
-        $this->fail($msg);
+        $this->fail($message);
       }
       catch (\InvalidArgumentException $e) {
         $this->assertTrue(preg_match('/^An invalid property name, .+ was specified. Allowed property names are:/', $e->getMessage()), 'Found expected exception message.');
-        $this->pass($msg);
+        $this->pass($message);
       }
     }
     $this->addMenuLink('test_link.1', '', 'test', array(), 'menu1');