diff --git a/modules/gallery_unit_test/helpers/diff.php b/modules/gallery_unit_test/helpers/diff.php
deleted file mode 100644
index 7b573732..00000000
--- a/modules/gallery_unit_test/helpers/diff.php
+++ /dev/null
@@ -1,26 +0,0 @@
-<?php defined("SYSPATH") or die("No direct script access.");
-/**
- * Gallery - a web based photo album viewer and editor
- * Copyright (C) 2000-2009 Bharat Mediratta
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or (at
- * your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA  02110-1301, USA.
- */
-class diff_Core {
-  static function compare($a, $b) {
-    fwrite(fopen($a_name = tempnam("/tmp", "test"), "w"), $a);
-    fwrite(fopen($b_name = tempnam("/tmp", "test"), "w"), $b);
-    return `diff $a_name $b_name`;
-  }
-}
diff --git a/modules/gallery_unit_test/helpers/test.php b/modules/gallery_unit_test/helpers/test.php
index 3e116808..91bd1be5 100644
--- a/modules/gallery_unit_test/helpers/test.php
+++ b/modules/gallery_unit_test/helpers/test.php
@@ -82,4 +82,10 @@ class test_Core {
     // Reload so that ORM coerces all fields into strings.
     return $tag->save()->reload();
   }
+
+  static function diff($a, $b) {
+    fwrite(fopen($a_name = tempnam("/tmp", "test"), "w"), $a);
+    fwrite(fopen($b_name = tempnam("/tmp", "test"), "w"), $b);
+    return `diff $a_name $b_name`;
+  }
 }
diff --git a/modules/gallery_unit_test/libraries/Gallery_Unit_Test_Case.php b/modules/gallery_unit_test/libraries/Gallery_Unit_Test_Case.php
index 509b4125..545af0fe 100644
--- a/modules/gallery_unit_test/libraries/Gallery_Unit_Test_Case.php
+++ b/modules/gallery_unit_test/libraries/Gallery_Unit_Test_Case.php
@@ -24,7 +24,7 @@ class Gallery_Unit_Test_Case extends Unit_Test_Case {
         sprintf("Expected (%s) %s but received (%s) %s\n Diff: %s",
                 gettype($expected), var_export($expected, true),
                 gettype($actual), var_export($actual, true),
-                diff::compare(var_export($expected, true), var_export($actual, true))),
+                test::diff(var_export($expected, true), var_export($actual, true))),
         $debug);
     }
     return $this;