check that cassette contains things before returning

tests/unit/test_cassettes.py

@@ -1,4 +1,4 @@
-import mock
+import pytest
 import yaml
 from vcr.cassette import Cassette
 
@@ -56,4 +56,5 @@ def test_cassette_response():
 
 def test_cassette_missing_response():
     a = Cassette('test')
-    assert not a.response('foo')
+    with pytest.raises(KeyError):
+        a.response('foo')

vcr/cassette.py

@@ -38,7 +38,7 @@ class Cassette(object):
         } for req, res in zip(self._requests, self._responses)])
 
     def deserialize(self, source):
-        '''Given a seritalized version, load the requests'''
+        '''Given a serialized version, load the requests'''
         self._requests, self._responses = (
             [r['request'] for r in source], [r['response'] for r in source])
 
@@ -49,7 +49,7 @@ class Cassette(object):
         self.play_count += 1
 
     def append(self, request, response):
-        '''Add a pair of request, response pairs to this cassette'''
+        '''Add a pair of request, response to this cassette'''
         self._requests.append(request)
         self._responses.append(response)
 
@@ -70,8 +70,7 @@ class Cassette(object):
         try:
             return self._responses[self._requests.index(request)]
         except ValueError:
-            #todo: keyerror if not in cassette
-            return None
+            raise KeyError
 
     def __enter__(self):
         '''Patch the fetching libraries we know about'''

vcr/stubs/__init__.py

@@ -65,13 +65,13 @@ class VCRConnectionMixin:
         '''Retrieve a the response'''
         # Check to see if the cassette has a response for this request. If so,
         # then return it
+        if self._request in self.cassette:
             response = self.cassette.response(self._request)
-        if response:
             # Alert the cassette to the fact that we've served another
             # response for the provided requests
             self.cassette.mark_played()
             return VCRHTTPResponse(response)
-
+        else:
             # Otherwise, we made an actual request, and should return the response
             # we got from the actual connection
             response = HTTPConnection.getresponse(self)