Index: drupal_web_test_case.php
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/simpletest/drupal_web_test_case.php,v
retrieving revision 1.2.2.3.2.38
diff -u -r1.2.2.3.2.38 drupal_web_test_case.php
--- drupal_web_test_case.php	25 Apr 2009 22:14:54 -0000	1.2.2.3.2.38
+++ drupal_web_test_case.php	4 Sep 2009 16:42:01 -0000
@@ -620,6 +620,12 @@
 //      $files = file_scan_directory($path, '/' . $type . '\-.*/');
       $files = file_scan_directory($path, '' . $type . '\-.*');
 
+      //if a file is still not found, then check simpletests files directory.
+      if (!$files) {
+        $path = drupal_get_path('module', 'simpletest') .'/files';
+        $files = file_scan_directory($path, '' . $type . '\-.*');
+      }
+
       // If size is set then remove any files that are not of that size.
       if ($size !== NULL) {
         foreach ($files as $file) {