Fix Zend_Navigation tests so it does not fail on Windows

tests/Zend/Navigation/PageFactoryTest.php

@@ -155,7 +155,7 @@ class Zend_Navigation_PageFactoryTest extends PHPUnit_Framework_TestCase
             );
         } catch(Zend_Exception $e) {
             $this->assertEquals(
-                'File "My/NonExistant/Page.php" does not exist or class '
+                'File "My' . DIRECTORY_SEPARATOR . 'NonExistant' . DIRECTORY_SEPARATOR . 'Page.php" does not exist or class '
                 . '"My_NonExistant_Page" was not found in the file',
                 $e->getMessage()
             );