Fix failing rcube_utils::strtotime() test if system timezone was different than expected

tests/Framework/Utils.php

@@ -275,18 +275,21 @@ class Framework_Utils extends PHPUnit_Framework_TestCase
      */
     function test_strtotime()
     {
+        // this test depends on system timezone if not set
+        date_default_timezone_set('UTC');
+
         $test = array(
             '1' => 1,
             '' => 0,
             'abc-555' => 0,
-            '2013-04-22' => 1366581600,
-            '2013/04/22' => 1366581600,
-            '2013.04.22' => 1366581600,
-            '22-04-2013' => 1366581600,
-            '22/04/2013' => 1366581600,
-            '22.04.2013' => 1366581600,
-            '22.4.2013'  => 1366581600,
-            '20130422'   => 1366581600,
+            '2013-04-22' => 1366588800,
+            '2013/04/22' => 1366588800,
+            '2013.04.22' => 1366588800,
+            '22-04-2013' => 1366588800,
+            '22/04/2013' => 1366588800,
+            '22.04.2013' => 1366588800,
+            '22.4.2013'  => 1366588800,
+            '20130422'   => 1366588800,
             '2013/06/21 12:00:00 UTC' => 1371816000,
             '2013/06/21 12:00:00 Europe/Berlin' => 1371808800,
         );