diff --git a/core/modules/system/lib/Drupal/system/Tests/Validation/ComplexDataConstraintValidatorTest.php b/core/modules/system/lib/Drupal/system/Tests/Validation/ComplexDataConstraintValidatorTest.php
index 05ef958..c11ff04 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Validation/ComplexDataConstraintValidatorTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Validation/ComplexDataConstraintValidatorTest.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\system\Tests\Validation;
 
+use Drupal\Core\TypedData\DataDefinition;
 use Drupal\simpletest\DrupalUnitTestBase;
 
 /**
@@ -23,7 +24,7 @@ class ComplexDataConstraintValidatorTest extends DrupalUnitTestBase {
 
   public static function getInfo() {
     return array(
-      'name' => 'Tests ComplexData validation constraint',
+      'name' => 'Complex data constraint',
       'description' => 'Tests ComplexData validation constraint with both valid and invalid values for a key',
       'group' => 'Validation',
     );
@@ -31,28 +32,22 @@ public static function getInfo() {
 
   public function setUp() {
     parent::setUp();
-
     $this->typedData = $this->container->get('typed_data');
   }
 
   /**
-   * Tests the ComplexData validation constraint validator by creating a
-   * typedData map definition with a ComplexData constraint containing one
-   * AllowedValues constraint, and then by tring to create a typedData object
-   * with both an allowed and a dissalowed value.
+   * Tests the ComplexData validation constraint validator.
+   *
+   * For testing a map including a constraint on one of its keys is defined.
    */
   public function testValidation() {
-    // Create a definition that specifies some ComplexData.
-    $definition = array(
-      'type' => 'map',
-      'constraints' => array(
-        'ComplexData' => array(
-          'key' => array(
-            'AllowedValues' => array(1,2,3)
-          ),
+    // Create a definition that specifies some ComplexData constraint.
+    $definition = DataDefinition::create('map')
+      ->addConstraint('ComplexData', array(
+        'key' => array(
+          'AllowedValues' => array(1, 2, 3)
         ),
-      ),
-    );
+      ));
 
     // Test the validation.
     $typed_data = $this->typedData->create($definition, array('key' => 1));
@@ -69,6 +64,23 @@ public function testValidation() {
     $this->assertEqual($violation->getMessage(), t('The value you selected is not a valid choice.'), 'The message for invalid value is correct.');
     $this->assertEqual($violation->getRoot(), $typed_data, 'Violation root is correct.');
     $this->assertEqual($violation->getInvalidValue(), 4, 'The invalid value is set correctly in the violation.');
+
+    // Test using the constraint with a map without the specified key. This
+    // should be ignored as long as there is no NotNull or NotBlank constraint.
+    $typed_data = $this->typedData->create($definition, array('foo' => 'bar'));
+    $violations = $typed_data->validate();
+    $this->assertEqual($violations->count(), 0, 'Not existing key is ignored.');
+
+    $definition = DataDefinition::create('map')
+      ->addConstraint('ComplexData', array(
+        'key' => array(
+          'NotNull' => array()
+        ),
+      ));
+
+    $typed_data = $this->typedData->create($definition, array('foo' => 'bar'));
+    $violations = $typed_data->validate();
+    $this->assertEqual($violations->count(), 1, 'Key is required.');
   }
 
 }