cookie parser: do not fail on cookie with empty value

https://fedorahosted.org/freeipa/ticket/5709

Reviewed-By: Martin Basti <mbasti@redhat.com>

ipapython/cookie.py

@@ -272,8 +272,9 @@ class Cookie(object):
             if match:
                 key = match.group(1)
                 value = match.group(2)
+
                 # Double quoted value?
-                if value[0] == '"':
+                if value and value[0] == '"':
                     if value[-1] == '"':
                         value = value[1:-1]
                     else:

ipatests/test_ipapython/test_cookie.py

@@ -50,6 +50,22 @@ class TestParse(unittest.TestCase):
         with self.assertRaises(ValueError):
             cookies = Cookie.parse(s)
 
+        # 1 cookie with empty value
+        s = 'color='
+        cookies = Cookie.parse(s)
+        self.assertEqual(len(cookies), 1)
+        cookie = cookies[0]
+        self.assertEqual(cookie.key, 'color')
+        self.assertEqual(cookie.value, '')
+        self.assertEqual(cookie.domain, None)
+        self.assertEqual(cookie.path, None)
+        self.assertEqual(cookie.max_age, None)
+        self.assertEqual(cookie.expires, None)
+        self.assertEqual(cookie.secure, None)
+        self.assertEqual(cookie.httponly, None)
+        self.assertEqual(str(cookie), "color=")
+        self.assertEqual(cookie.http_cookie(), "color=;")
+
         # 1 cookie with name/value
         s = 'color=blue'
         cookies = Cookie.parse(s)