diff --git a/core/modules/system/src/Tests/Entity/EntityFormTest.php b/core/modules/system/src/Tests/Entity/EntityFormTest.php
index 307b69a..dcdb20f 100644
--- a/core/modules/system/src/Tests/Entity/EntityFormTest.php
+++ b/core/modules/system/src/Tests/Entity/EntityFormTest.php
@@ -66,6 +66,8 @@ protected function doTestFormCRUD($entity_type) {
     );
 
     $this->drupalPostForm($entity_type . '/add', $edit, t('Save'));
+    $this->assertNoRaw('This should not run.');
+
     $entity = $this->loadEntityByName($entity_type, $name1);
     $this->assertTrue($entity, format_string('%entity_type: Entity found in the database.', array('%entity_type' => $entity_type)));
 
diff --git a/core/modules/system/tests/modules/entity_test/src/EntityTestForm.php b/core/modules/system/tests/modules/entity_test/src/EntityTestForm.php
index ec7c3e0..0f13979 100644
--- a/core/modules/system/tests/modules/entity_test/src/EntityTestForm.php
+++ b/core/modules/system/tests/modules/entity_test/src/EntityTestForm.php
@@ -43,6 +43,7 @@ public function form(array $form, FormStateInterface $form_state) {
         '#default_value' => $entity->isNewRevision(),
       );
     }
+    $form['#validate'][] = '::formLevelValidator';
 
     return $form;
   }
@@ -50,6 +51,13 @@ public function form(array $form, FormStateInterface $form_state) {
   /**
    * {@inheritdoc}
    */
+  public function formLevelValidator(array &$form, FormStateInterface $form_state) {
+    $form_state->setError($form, 'This should not run.');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
   public function save(array $form, FormStateInterface $form_state) {
     $entity = $this->entity;
 
diff --git a/core/tests/Drupal/Tests/Core/Entity/EntityFormTest.php b/core/tests/Drupal/Tests/Core/Entity/EntityFormTest.php
index ea39a9d..b703d45 100644
--- a/core/tests/Drupal/Tests/Core/Entity/EntityFormTest.php
+++ b/core/tests/Drupal/Tests/Core/Entity/EntityFormTest.php
@@ -9,6 +9,7 @@
 
 use Drupal\Core\Entity\EntityForm;
 use Drupal\Core\Form\FormState;
+use Drupal\Core\Form\FormStateInterface;
 use Drupal\Tests\UnitTestCase;
 
 /**
@@ -123,4 +124,20 @@ public function testCopyFormValuesToEntity() {
     $this->assertNull($result->get('key_controlled_by_plugin_collection'));
   }
 
+  /**
+   * @covers ::validate
+   */
+  public function testValidate() {
+    $form_object = $this->getMock('Drupal\Core\Entity\EntityFormInterface');
+    $form_object->expects($this->once())
+      ->method('validate')
+      ->willReturnCallback(function (array &$form, FormStateInterface $form_state) {
+        $form['foo'] = 'bar';
+      });
+    $form['baz'] = 'bim';
+    $form_state = new FormState();
+    $form_object->validate($form, $form_state);
+    $this->assertArrayHasKey('foo', $form);
+  }
+
 }