diff --git a/modules/simpletest/drupal_web_test_case.php b/modules/simpletest/drupal_web_test_case.php
index 2f5c5b08381bce0f9a7b7cfc218b68344d6dec63..eb18ef4a4da388ac935d3d9565753d8700a50bf8 100644
--- a/modules/simpletest/drupal_web_test_case.php
+++ b/modules/simpletest/drupal_web_test_case.php
@@ -1082,10 +1082,12 @@ protected function setUp() {
     // Use temporary files directory with the same prefix as the database.
     $public_files_directory  = $this->originalFileDirectory . '/simpletest/' . substr($db_prefix, 10);
     $private_files_directory = $public_files_directory . '/private';
+    $temp_files_directory    = $private_files_directory . '/temp';
 
     // Create the directories
     file_prepare_directory($public_files_directory, FILE_CREATE_DIRECTORY | FILE_MODIFY_PERMISSIONS);
     file_prepare_directory($private_files_directory, FILE_CREATE_DIRECTORY);
+    file_prepare_directory($temp_files_directory, FILE_CREATE_DIRECTORY);
 
     // Log fatal errors.
     ini_set('log_errors', 1);
@@ -1150,6 +1152,7 @@ protected function setUp() {
     // Set path variables
     variable_set('file_public_path', $public_files_directory);
     variable_set('file_private_path', $private_files_directory);
+    variable_set('file_temporary_path', $temp_files_directory);
 
     // Use the test mail class instead of the default mail handler class.
     variable_set('mail_system', array('default-system' => 'TestingMailSystem'));
diff --git a/modules/simpletest/tests/file.test b/modules/simpletest/tests/file.test
index 051d57889f3b8628dba7f88c13d21deccd56b6dd..0644d3910cc7e2a8840a1b5a939d7b06c3f2f3e1 100644
--- a/modules/simpletest/tests/file.test
+++ b/modules/simpletest/tests/file.test
@@ -2195,7 +2195,7 @@ class StreamWrapperTest extends DrupalWebTestCase {
     $this->assertEqual(file_build_uri('foo/bar.txt'), 'public://foo/bar.txt', t('Expected scheme was added.'));
     $this->assertEqual(file_directory_path(), variable_get('file_public_path'), t('Expected default directory path was returned.'));
     $this->assertEqual(file_directory_path('public'), variable_get('file_public_path'), t('Expected public directory path was returned.'));
-    $this->assertEqual(file_directory_path('temporary'), conf_path() . '/private/temp', t('Expected temporary directory path was returned.'));
+    $this->assertEqual(file_directory_path('temporary'), variable_get('file_temporary_path'), t('Expected temporary directory path was returned.'));
     $this->assertEqual(file_directory_path($this->scheme), variable_get('stream_public_path', 'sites/default/files'), t('Expected dummy directory path was returned.'));
     $this->assertFalse(file_directory_path('non-existent'), t('No directory path returned for invalid scheme.'));
     variable_set('file_default_scheme', 'private');