diff --git a/tests/test_downloader_handlers.py b/tests/test_downloader_handlers.py
index c69bd3da1..8835267fe 100644
--- a/tests/test_downloader_handlers.py
+++ b/tests/test_downloader_handlers.py
@@ -109,6 +109,7 @@ class FileTestCase(unittest.TestCase):
 
     def setUp(self):
         self.tmpname = self.mktemp()
+        # add a special char to check that they are handled correctly
         with open(self.tmpname + '^', 'w') as f:
             f.write('0123456789')
         handler = create_instance(FileDownloadHandler, None, get_crawler())