=== modified file 'django/test/client.py'
--- django/test/client.py	2008-11-12 11:22:05 +0000
+++ django/test/client.py	2010-01-28 09:20:55 +0000
@@ -187,7 +187,7 @@
         using the arguments to the request.
         """
         environ = {
-            'HTTP_COOKIE':      self.cookies,
+            'HTTP_COOKIE':      self.cookies.output(header='', sep='; '),
             'PATH_INFO':         '/',
             'QUERY_STRING':      '',
             'REQUEST_METHOD':    'GET',