Expose Fake objects in compat

The FakeHTTPMessage and FakeHTTPResponse objects were only defined for
old versions of requests to provide compatibility. It turns out we need
these for cookie extraction in new versions as well so always define the
object and leave the old compatibility check.

Change-Id: Ifb42fd1c6b1b895b26bee59632ad0dedd78a6256

requests_mock/compat.py

@@ -20,31 +20,41 @@ def _versiontuple(v):
 _requests_version = _versiontuple(requests.__version__)
 
 
-if _requests_version < (2, 3):
+class _FakeHTTPMessage(object):
 
+    def __init__(self, headers):
+        self.headers = headers
+
+    def getheaders(self, name):
+        try:
+            return [self.headers[name]]
+        except KeyError:
+            return []
+
+    def get_all(self, name, failobj=None):
+        # python 3 only, overrides email.message.Message.get_all
+        try:
+            return [self.headers[name]]
+        except KeyError:
+            return failobj
+
+
+class _FakeHTTPResponse(object):
+
+    def __init__(self, headers):
+        self.msg = _FakeHTTPMessage(headers)
+
+    def isclosed(self):
+        # Don't let urllib try to close me
+        return False
+
+
+if _requests_version < (2, 3):
     # NOTE(jamielennox): There is a problem with requests < 2.3.0 such that it
     # needs a httplib message for use with cookie extraction. It has been fixed
     # but it is needed until we can rely on a recent enough requests version.
 
-    class _FakeHTTPMessage(object):
-
-        def getheaders(self, name):
-            return None
-
-        def get_all(self, name, failobj=None):
-            # python 3 only, overrides email.message.Message.get_all
-            return failobj
-
-    class _FakeHTTPResponse(object):
-
-        def __init__(self):
-            self.msg = _FakeHTTPMessage()
-
-        def isclosed(self):
-            # Don't let urllib try to close me
-            return False
-
-    _fake_http_response = _FakeHTTPResponse()
+    _fake_http_response = _FakeHTTPResponse({})
 
 else:
     _fake_http_response = None