Experiment with implementation of a $COOKIE

$COOKIE is replaced by the cookie key and value pairs parsed out of
the set-cookie headers from the previous request.

This was straightforward to do and matches the behavior in
http://sandbox.tiddlyspace.com/_/979d0866-8959-4fed-9b3b-403002c20aa2
but for some reason it doesn't feel right. Needs more thought.

gabbi/case.py

@@ -30,6 +30,7 @@ from unittest import case
 
 import six
 from six.moves.urllib import parse as urlparse
+from six.moves import http_cookies
 import wsgi_intercept
 
 from gabbi import __version__
@@ -44,6 +45,7 @@ REPLACERS = [
     'NETLOC',
     'ENVIRON',
     'LOCATION',
+    'COOKIE',
     'LAST_URL',
     'HEADERS',
     'RESPONSE',
@@ -208,6 +210,17 @@ class HTTPTestCase(unittest.TestCase):
             raise ValueError(
                 "JSONPath '%s' failed to match on data: '%s'" % (path, data))
 
+    def _cookie_replace(self, message):
+        """Replace $COOKIE in a message.
+
+        With cookie data from set-cookie in the prior request.
+        """
+        response_cookies = self.prior.response['set-cookie']
+        cookies = http_cookies.SimpleCookie()
+        cookies.load(response_cookies)
+        cookie_string = cookies.output(attrs=[], header='', sep=',').strip()
+        return message.replace('$COOKIE', cookie_string)
+
     def _headers_replace(self, message):
         """Replace a header indicator in a message with that headers value from
         the prior request.

gabbi/tests/gabbits_intercept/cookie.yaml

@@ -0,0 +1,12 @@
+
+tests:
+- name: get a cookie
+  GET: /cookie
+  response_headers:
+      set-cookie: session=1234; domain=.example.com
+
+- name: use that cookie in a URL
+  desc: just to get it somewhere we can test it and confirm domain is dropped
+  GET: /cookie?$COOKIE
+  response_headers:
+      x-gabbi-url: $SCHEME://$NETLOC/cookie?session=1234

gabbi/tests/simple_wsgi.py

@@ -105,6 +105,8 @@ class SimpleWsgi(object):
                 else:
                     CURRENT_POLL = 0
             # fall through if we've ended the loop
+        elif path_info == '/cookie':
+            headers.append(('Set-Cookie', 'session=1234; domain=.example.com'))
 
         start_response('200 OK', headers)