diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigFormOverrideTest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigFormOverrideTest.php
index 2153952..5a22e90 100644
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigFormOverrideTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigFormOverrideTest.php
@@ -31,19 +31,31 @@ public static function getInfo() {
   public function testFormsWithOverrides() {
     $this->drupalLogin($this->drupalCreateUser(array('access administration pages', 'administer site configuration')));
 
-    $overridden_name = $GLOBALS['config']['system.site']['name'] = 'Site name global conf override';
-    $config_factory = \Drupal::configFactory();
-    $config_factory->setOverrideState(FALSE);
+    $overridden_name = 'Site name global conf override';
 
+    // Set up an override.
+    $settings['config']['system.site']['name'] = (object) array(
+      'value' => $overridden_name,
+      'required' => TRUE,
+    );
+    $this->writeSettings($settings);
+    \Drupal::configFactory()->setOverrideState(TRUE);
+
+    // Test that everything on the form is the same, but that the override
+    // worked for the actual site name.
     $this->drupalGet('admin/config/system/site-information');
-    $this->assertText($overridden_name);
+    $this->assertTitle('Site information | ' . $overridden_name);
+    $elements = $this->xpath('//input[@name="site_name"]');
+    $this->assertIdentical((string) $elements[0]['value'], 'Drupal');
 
-    $config_factory->setOverrideState(TRUE);
-    $this->drupalGet('admin/config/system/site-information');
-    $this->assertNoText($overridden_name);
-
-    $this->drupalPostForm('admin/config/system/site-information', array(), t('Save configuration'));
-    $this->assertNotEqual($overridden_name, $config_factory->get('system.site')->get('name'));
+    // Submit the form and ensure the site name is not changed.
+    $edit = array(
+      'site_name' => 'Custom site name',
+    );
+    $this->drupalPostForm('admin/config/system/site-information', $edit, t('Save configuration'));
+    $this->assertTitle('Site information | ' . $overridden_name);
+    $elements = $this->xpath('//input[@name="site_name"]');
+    $this->assertIdentical((string) $elements[0]['value'], $edit['site_name']);
   }
 
 }