diff --git a/core/modules/system/lib/Drupal/system/Tests/File/HtaccessUnitTest.php b/core/modules/system/lib/Drupal/system/Tests/File/HtaccessUnitTest.php
index e98097c..5f4b656 100644
--- a/core/modules/system/lib/Drupal/system/Tests/File/HtaccessUnitTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/File/HtaccessUnitTest.php
@@ -7,19 +7,18 @@
 
 namespace Drupal\system\Tests\File;
 
+use Drupal\Component\Utility\String;
 use Drupal\simpletest\DrupalUnitTestBase;
 
 /**
- * File system configuration related tests.
- *
- * @todo Use UnitTestBase after removing container dependency from error handler.
+ * .htaccess file saving tests.
  */
 class HtaccessUnitTest extends DrupalUnitTestBase {
 
   public static function getInfo() {
     return array(
-      'name' => '.htaccess file test',
-      'description' => 'Tests .htaccess file saving',
+      'name' => '.htaccess file saving',
+      'description' => 'Tests .htaccess file saving.',
       'group' => 'File API',
     );
   }
@@ -45,7 +44,7 @@ function testHtaccessSave() {
     $this->assertTrue(file_save_htaccess($public, FALSE));
     $content = file_get_contents($public . '/.htaccess');
     $this->assertIdentical($content, "SetHandler Drupal_Security_Do_Not_Remove_See_SA_2006_006\nOptions None\nOptions +FollowSymLinks");
-    $this->assertIdentical(fileperms($public . '/.htaccess') & 0777, 0444);
+    $this->assertFilePermissions($public . '/.htaccess', 0444);
 
     $this->assertTrue(file_save_htaccess($public, FALSE));
 
@@ -54,7 +53,7 @@ function testHtaccessSave() {
     $this->assertTrue(file_save_htaccess($private));
     $content = file_get_contents($private . '/.htaccess');
     $this->assertIdentical($content, "SetHandler Drupal_Security_Do_Not_Remove_See_SA_2006_006\nDeny from all\nOptions None\nOptions +FollowSymLinks");
-    $this->assertIdentical(fileperms($private . '/.htaccess') & 0777, 0444);
+    $this->assertFilePermissions($private . '/.htaccess', 0444);
 
     $this->assertTrue(file_save_htaccess($private));
 
@@ -63,9 +62,29 @@ function testHtaccessSave() {
     $this->assertTrue(file_save_htaccess($stream));
     $content = file_get_contents($stream . '/.htaccess');
     $this->assertIdentical($content, "SetHandler Drupal_Security_Do_Not_Remove_See_SA_2006_006\nDeny from all\nOptions None\nOptions +FollowSymLinks");
-    $this->assertIdentical(fileperms($stream . '/.htaccess') & 0777, 0444);
+    $this->assertFilePermissions($stream . '/.htaccess', 0444);
 
     $this->assertTrue(file_save_htaccess($stream));
   }
 
+  /**
+   * Asserts expected file permissions for a given file.
+   *
+   * @param string $uri
+   *   The URI of the file to check.
+   * @param int $expected
+   *   The expected file permissions; e.g., 0444.
+   *
+   * @return bool
+   *   Whether the actual file permissions match the expected.
+   */
+  protected function assertFilePermissions($uri, $expected) {
+    $actual = fileperms($uri) & 0777;
+    return $this->assertIdentical($actual, $expected, String::format('@uri file permissions @actual are identical to @expected.', array(
+      '@uri' => $uri,
+      '@actual' => 0 . decoct($actual),
+      '@expected' => 0 . decoct($expected),
+    )));
+  }
+
 }