diff --git a/core/includes/install.inc b/core/includes/install.inc
index 2ee8371..1b3d9a3 100644
--- a/core/includes/install.inc
+++ b/core/includes/install.inc
@@ -209,7 +209,7 @@ function drupal_rewrite_settings($settings = array(), $settings_file = NULL) {
   $contents = file_get_contents(DRUPAL_ROOT . '/' . $settings_file);
   if ($contents !== FALSE) {
     // Initialize the contents for the settings.php file if it is empty.
-    if ($contents == '') {
+    if (trim($contents) === '') {
       $contents = "<?php\n";
     }
     // Step through each token in settings.php and replace any variables that
diff --git a/core/modules/system/lib/Drupal/system/Tests/System/SettingsRewriteTest.php b/core/modules/system/lib/Drupal/system/Tests/System/SettingsRewriteTest.php
index 1c9f463..beeab3d 100644
--- a/core/modules/system/lib/Drupal/system/Tests/System/SettingsRewriteTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/System/SettingsRewriteTest.php
@@ -114,19 +114,19 @@ function testDrupalRewriteSettings() {
     // Set the array of settings that will be written to the file.
     $test = array(
       'settings' => array(
-        'no_index_value_scalar' => (object) array(
-          'value' => FALSE,
-          'comment' => 'comment',
-          'required' => TRUE,
+        'no_index' => (object) array(
+          'value' => TRUE,
+          'required' => TRUE,
         ),
       ),
-      'expected' => '$no_index_value_scalar = false; // comment'
+      'expected' => '$no_index = TRUE;'
     );
     // Make an empty file.
-    $filename = variable_get('file_public_path', conf_path() . '/files') . '/empty_settings.php';
+    $filename = settings()->get('file_public_path', conf_path() . '/files') . '/mock_settings.php';
     file_put_contents(DRUPAL_ROOT . '/' . $filename, "");
+
     // Write the setting to the file.
     drupal_rewrite_settings($test['settings'], $filename);
+
     // Check that the result is just the php opening tag and the settings.
     $this->assertEqual(file_get_contents(DRUPAL_ROOT . '/' . $filename), "<?php\n" . $test['expected'] . "\n");
   }