diff --git a/tests/test_http.py b/tests/test_http.py
index 67e8aa6..cb7a832 100644
--- a/tests/test_http.py
+++ b/tests/test_http.py
@@ -35,6 +35,52 @@
 from apiclient.http import MediaInMemoryUpload
 from apiclient.http import set_user_agent
 from apiclient.model import JsonModel
+from oauth2client.client import Credentials
+
+
+class MockCredentials(Credentials):
+  """Mock class for all Credentials objects."""
+  def __init__(self, bearer_token):
+    super(MockCredentials, self).__init__()
+    self._authorized = 0
+    self._refreshed = 0
+    self._applied = 0
+    self._bearer_token = bearer_token
+
+  def authorize(self, http):
+    self._authorized += 1
+
+    request_orig = http.request
+
+    # The closure that will replace 'httplib2.Http.request'.
+    def new_request(uri, method='GET', body=None, headers=None,
+                    redirections=httplib2.DEFAULT_MAX_REDIRECTS,
+                    connection_type=None):
+      # Modify the request headers to add the appropriate
+      # Authorization header.
+      if headers is None:
+        headers = {}
+      self.apply(headers)
+
+      resp, content = request_orig(uri, method, body, headers,
+                                   redirections, connection_type)
+
+      return resp, content
+
+    # Replace the request method with our own closure.
+    http.request = new_request
+
+    # Set credentials as a property of the request method.
+    setattr(http.request, 'credentials', self)
+
+    return http
+
+  def refresh(self, http):
+    self._refreshed += 1
+
+  def apply(self, headers):
+    self._applied += 1
+    headers['authorization'] = self._bearer_token + ' ' + str(self._refreshed)
 
 
 DATA_DIR = os.path.join(os.path.dirname(__file__), 'data')
@@ -52,7 +98,7 @@
 
     http = set_user_agent(http, "my_app/5.5")
     resp, content = http.request("http://example.com")
-    self.assertEqual(content['user-agent'], 'my_app/5.5')
+    self.assertEqual('my_app/5.5', content['user-agent'])
 
   def test_set_user_agent_nested(self):
     http = HttpMockSequence([
@@ -62,25 +108,25 @@
     http = set_user_agent(http, "my_app/5.5")
     http = set_user_agent(http, "my_library/0.1")
     resp, content = http.request("http://example.com")
-    self.assertEqual(content['user-agent'], 'my_app/5.5 my_library/0.1')
+    self.assertEqual('my_app/5.5 my_library/0.1', content['user-agent'])
 
   def test_media_file_upload_to_from_json(self):
     upload = MediaFileUpload(
         datafile('small.png'), chunksize=500, resumable=True)
-    self.assertEquals('image/png', upload.mimetype())
-    self.assertEquals(190, upload.size())
-    self.assertEquals(True, upload.resumable())
-    self.assertEquals(500, upload.chunksize())
-    self.assertEquals('PNG', upload.getbytes(1, 3))
+    self.assertEqual('image/png', upload.mimetype())
+    self.assertEqual(190, upload.size())
+    self.assertEqual(True, upload.resumable())
+    self.assertEqual(500, upload.chunksize())
+    self.assertEqual('PNG', upload.getbytes(1, 3))
 
     json = upload.to_json()
     new_upload = MediaUpload.new_from_json(json)
 
-    self.assertEquals('image/png', new_upload.mimetype())
-    self.assertEquals(190, new_upload.size())
-    self.assertEquals(True, new_upload.resumable())
-    self.assertEquals(500, new_upload.chunksize())
-    self.assertEquals('PNG', new_upload.getbytes(1, 3))
+    self.assertEqual('image/png', new_upload.mimetype())
+    self.assertEqual(190, new_upload.size())
+    self.assertEqual(True, new_upload.resumable())
+    self.assertEqual(500, new_upload.chunksize())
+    self.assertEqual('PNG', new_upload.getbytes(1, 3))
 
   def test_http_request_to_from_json(self):
 
@@ -103,13 +149,13 @@
     json = req.to_json()
     new_req = HttpRequest.from_json(json, http, _postproc)
 
-    self.assertEquals(new_req.headers,
-                      {'content-type':
-                       'multipart/related; boundary="---flubber"'})
-    self.assertEquals(new_req.uri, 'http://example.com')
-    self.assertEquals(new_req.body, '{}')
-    self.assertEquals(new_req.http, http)
-    self.assertEquals(new_req.resumable.to_json(), media_upload.to_json())
+    self.assertEqual({'content-type':
+                       'multipart/related; boundary="---flubber"'},
+                       new_req.headers)
+    self.assertEqual('http://example.com', new_req.uri)
+    self.assertEqual('{}', new_req.body)
+    self.assertEqual(http, new_req.http)
+    self.assertEqual(media_upload.to_json(), new_req.resumable.to_json())
 
 EXPECTED = """POST /someapi/v1/collection/?foo=bar HTTP/1.1
 Content-Type: application/json
@@ -153,6 +199,50 @@
 --batch_foobarbaz--"""
 
 
+BATCH_RESPONSE_WITH_401 = """--batch_foobarbaz
+Content-Type: application/http
+Content-Transfer-Encoding: binary
+Content-ID: <randomness+1>
+
+HTTP/1.1 401 Authoration Required
+Content-Type application/json
+Content-Length: 14
+ETag: "etag/pony"\r\n\r\n{"error": {"message":
+  "Authorizaton failed."}}
+
+--batch_foobarbaz
+Content-Type: application/http
+Content-Transfer-Encoding: binary
+Content-ID: <randomness+2>
+
+HTTP/1.1 200 OK
+Content-Type application/json
+Content-Length: 14
+ETag: "etag/sheep"\r\n\r\n{"baz": "qux"}
+--batch_foobarbaz--"""
+
+
+BATCH_SINGLE_RESPONSE = """--batch_foobarbaz
+Content-Type: application/http
+Content-Transfer-Encoding: binary
+Content-ID: <randomness+1>
+
+HTTP/1.1 200 OK
+Content-Type application/json
+Content-Length: 14
+ETag: "etag/pony"\r\n\r\n{"foo": 42}
+--batch_foobarbaz--"""
+
+class Callbacks(object):
+  def __init__(self):
+    self.responses = {}
+    self.exceptions = {}
+
+  def f(self, request_id, response, exception):
+    self.responses[request_id] = response
+    self.exceptions[request_id] = exception
+
+
 class TestBatch(unittest.TestCase):
 
   def setUp(self):
@@ -196,7 +286,7 @@
         methodId=None,
         resumable=None)
     s = batch._serialize_request(request).splitlines()
-    self.assertEquals(s, EXPECTED.splitlines())
+    self.assertEqual(EXPECTED.splitlines(), s)
 
   def test_serialize_request_media_body(self):
     batch = BatchHttpRequest()
@@ -213,9 +303,9 @@
         headers={'content-type': 'application/json'},
         methodId=None,
         resumable=None)
+    # Just testing it shouldn't raise an exception.
     s = batch._serialize_request(request).splitlines()
 
-
   def test_serialize_request_no_body(self):
     batch = BatchHttpRequest()
     request = HttpRequest(
@@ -228,30 +318,30 @@
         methodId=None,
         resumable=None)
     s = batch._serialize_request(request).splitlines()
-    self.assertEquals(s, NO_BODY_EXPECTED.splitlines())
+    self.assertEqual(NO_BODY_EXPECTED.splitlines(), s)
 
   def test_deserialize_response(self):
     batch = BatchHttpRequest()
     resp, content = batch._deserialize_response(RESPONSE)
 
-    self.assertEquals(resp.status, 200)
-    self.assertEquals(resp.reason, 'OK')
-    self.assertEquals(resp.version, 11)
-    self.assertEquals(content, '{"answer": 42}')
+    self.assertEqual(200, resp.status)
+    self.assertEqual('OK', resp.reason)
+    self.assertEqual(11, resp.version)
+    self.assertEqual('{"answer": 42}', content)
 
   def test_new_id(self):
     batch = BatchHttpRequest()
 
     id_ = batch._new_id()
-    self.assertEquals(id_, '1')
+    self.assertEqual('1', id_)
 
     id_ = batch._new_id()
-    self.assertEquals(id_, '2')
+    self.assertEqual('2', id_)
 
     batch.add(self.request1, request_id='3')
 
     id_ = batch._new_id()
-    self.assertEquals(id_, '4')
+    self.assertEqual('4', id_)
 
   def test_add(self):
     batch = BatchHttpRequest()
@@ -267,13 +357,6 @@
     self.assertRaises(BatchError, batch.add, self.request1, request_id='1')
 
   def test_execute(self):
-    class Callbacks(object):
-      def __init__(self):
-        self.responses = {}
-
-      def f(self, request_id, response):
-        self.responses[request_id] = response
-
     batch = BatchHttpRequest()
     callbacks = Callbacks()
 
@@ -285,8 +368,10 @@
        BATCH_RESPONSE),
       ])
     batch.execute(http)
-    self.assertEqual(callbacks.responses['1'], {'foo': 42})
-    self.assertEqual(callbacks.responses['2'], {'baz': 'qux'})
+    self.assertEqual({'foo': 42}, callbacks.responses['1'])
+    self.assertEqual(None, callbacks.exceptions['1'])
+    self.assertEqual({'baz': 'qux'}, callbacks.responses['2'])
+    self.assertEqual(None, callbacks.exceptions['2'])
 
   def test_execute_request_body(self):
     batch = BatchHttpRequest()
@@ -311,14 +396,82 @@
       header = parts[1].splitlines()[1]
       self.assertEqual('Content-Type: application/http', header)
 
+  def test_execute_refresh_and_retry_on_401(self):
+    batch = BatchHttpRequest()
+    callbacks = Callbacks()
+    cred_1 = MockCredentials('Foo')
+    cred_2 = MockCredentials('Bar')
+
+    http = HttpMockSequence([
+      ({'status': '200',
+        'content-type': 'multipart/mixed; boundary="batch_foobarbaz"'},
+       BATCH_RESPONSE_WITH_401),
+      ({'status': '200',
+        'content-type': 'multipart/mixed; boundary="batch_foobarbaz"'},
+       BATCH_SINGLE_RESPONSE),
+      ])
+
+    creds_http_1 = HttpMockSequence([])
+    cred_1.authorize(creds_http_1)
+
+    creds_http_2 = HttpMockSequence([])
+    cred_2.authorize(creds_http_2)
+
+    self.request1.http = creds_http_1
+    self.request2.http = creds_http_2
+
+    batch.add(self.request1, callback=callbacks.f)
+    batch.add(self.request2, callback=callbacks.f)
+    batch.execute(http)
+
+    self.assertEqual({'foo': 42}, callbacks.responses['1'])
+    self.assertEqual(None, callbacks.exceptions['1'])
+    self.assertEqual({'baz': 'qux'}, callbacks.responses['2'])
+    self.assertEqual(None, callbacks.exceptions['2'])
+
+    self.assertEqual(1, cred_1._refreshed)
+    self.assertEqual(0, cred_2._refreshed)
+
+    self.assertEqual(1, cred_1._authorized)
+    self.assertEqual(1, cred_2._authorized)
+
+    self.assertEqual(1, cred_2._applied)
+    self.assertEqual(2, cred_1._applied)
+
+  def test_http_errors_passed_to_callback(self):
+    batch = BatchHttpRequest()
+    callbacks = Callbacks()
+    cred_1 = MockCredentials('Foo')
+    cred_2 = MockCredentials('Bar')
+
+    http = HttpMockSequence([
+      ({'status': '200',
+        'content-type': 'multipart/mixed; boundary="batch_foobarbaz"'},
+       BATCH_RESPONSE_WITH_401),
+      ({'status': '200',
+        'content-type': 'multipart/mixed; boundary="batch_foobarbaz"'},
+       BATCH_RESPONSE_WITH_401),
+      ])
+
+    creds_http_1 = HttpMockSequence([])
+    cred_1.authorize(creds_http_1)
+
+    creds_http_2 = HttpMockSequence([])
+    cred_2.authorize(creds_http_2)
+
+    self.request1.http = creds_http_1
+    self.request2.http = creds_http_2
+
+    batch.add(self.request1, callback=callbacks.f)
+    batch.add(self.request2, callback=callbacks.f)
+    batch.execute(http)
+
+    self.assertEqual(None, callbacks.responses['1'])
+    self.assertEqual(401, callbacks.exceptions['1'].resp.status)
+    self.assertEqual({u'baz': u'qux'}, callbacks.responses['2'])
+    self.assertEqual(None, callbacks.exceptions['2'])
+
   def test_execute_global_callback(self):
-    class Callbacks(object):
-      def __init__(self):
-        self.responses = {}
-
-      def f(self, request_id, response):
-        self.responses[request_id] = response
-
     callbacks = Callbacks()
     batch = BatchHttpRequest(callback=callbacks.f)
 
@@ -330,8 +483,8 @@
        BATCH_RESPONSE),
       ])
     batch.execute(http)
-    self.assertEqual(callbacks.responses['1'], {'foo': 42})
-    self.assertEqual(callbacks.responses['2'], {'baz': 'qux'})
+    self.assertEqual({'foo': 42}, callbacks.responses['1'])
+    self.assertEqual({'baz': 'qux'}, callbacks.responses['2'])
 
   def test_media_inmemory_upload(self):
     media = MediaInMemoryUpload('abcdef', 'text/plain', chunksize=10,
diff --git a/tests/test_oauth2client.py b/tests/test_oauth2client.py
index d50d6a0..3e512a1 100644
--- a/tests/test_oauth2client.py
+++ b/tests/test_oauth2client.py
@@ -70,7 +70,7 @@
       ])
     http = self.credentials.authorize(http)
     resp, content = http.request("http://example.com")
-    self.assertEqual(content['authorization'], 'OAuth 1/3w')
+    self.assertEqual('Bearer 1/3w', content['Authorization'])
 
   def test_token_refresh_failure(self):
     http = HttpMockSequence([
@@ -95,11 +95,11 @@
   def test_to_from_json(self):
     json = self.credentials.to_json()
     instance = OAuth2Credentials.from_json(json)
-    self.assertEquals(type(instance), OAuth2Credentials)
+    self.assertEqual(OAuth2Credentials, type(instance))
     instance.token_expiry = None
     self.credentials.token_expiry = None
 
-    self.assertEquals(self.credentials.__dict__, instance.__dict__)
+    self.assertEqual(instance.__dict__, self.credentials.__dict__)
 
 
 class AccessTokenCredentialsTests(unittest.TestCase):
@@ -136,7 +136,7 @@
       ])
     http = self.credentials.authorize(http)
     resp, content = http.request('http://example.com')
-    self.assertEqual(content['authorization'], 'OAuth foo')
+    self.assertEqual('Bearer foo', content['Authorization'])
 
 
 class TestAssertionCredentials(unittest.TestCase):
@@ -155,8 +155,8 @@
 
   def test_assertion_body(self):
     body = urlparse.parse_qs(self.credentials._generate_refresh_request_body())
-    self.assertEqual(body['assertion'][0], self.assertion_text)
-    self.assertEqual(body['assertion_type'][0], self.assertion_type)
+    self.assertEqual(self.assertion_text, body['assertion'][0])
+    self.assertEqual(self.assertion_type, body['assertion_type'][0])
 
   def test_assertion_refresh(self):
     http = HttpMockSequence([
@@ -165,7 +165,7 @@
       ])
     http = self.credentials.authorize(http)
     resp, content = http.request("http://example.com")
-    self.assertEqual(content['authorization'], 'OAuth 1/3w')
+    self.assertEqual('Bearer 1/3w', content['Authorization'])
 
 
 class ExtractIdTokenText(unittest.TestCase):
@@ -177,7 +177,7 @@
     jwt = 'stuff.' + payload + '.signature'
 
     extracted = _extract_id_token(jwt)
-    self.assertEqual(body, extracted)
+    self.assertEqual(extracted, body)
 
   def test_extract_failure(self):
     body = {'foo': 'bar'}
@@ -201,11 +201,11 @@
 
     parsed = urlparse.urlparse(authorize_url)
     q = parse_qs(parsed[4])
-    self.assertEqual(q['client_id'][0], 'client_id+1')
-    self.assertEqual(q['response_type'][0], 'code')
-    self.assertEqual(q['scope'][0], 'foo')
-    self.assertEqual(q['redirect_uri'][0], 'OOB_CALLBACK_URN')
-    self.assertEqual(q['access_type'][0], 'offline')
+    self.assertEqual('client_id+1', q['client_id'][0])
+    self.assertEqual('code', q['response_type'][0])
+    self.assertEqual('foo', q['scope'][0])
+    self.assertEqual('OOB_CALLBACK_URN', q['redirect_uri'][0])
+    self.assertEqual('offline', q['access_type'][0])
 
   def test_override_flow_access_type(self):
     """Passing access_type overrides the default."""
@@ -220,11 +220,11 @@
 
     parsed = urlparse.urlparse(authorize_url)
     q = parse_qs(parsed[4])
-    self.assertEqual(q['client_id'][0], 'client_id+1')
-    self.assertEqual(q['response_type'][0], 'code')
-    self.assertEqual(q['scope'][0], 'foo')
-    self.assertEqual(q['redirect_uri'][0], 'OOB_CALLBACK_URN')
-    self.assertEqual(q['access_type'][0], 'online')
+    self.assertEqual('client_id+1', q['client_id'][0])
+    self.assertEqual('code', q['response_type'][0])
+    self.assertEqual('foo', q['scope'][0])
+    self.assertEqual('OOB_CALLBACK_URN', q['redirect_uri'][0])
+    self.assertEqual('online', q['access_type'][0])
 
   def test_exchange_failure(self):
     http = HttpMockSequence([
@@ -246,9 +246,9 @@
       ])
 
     credentials = self.flow.step2_exchange('some random code', http)
-    self.assertEqual(credentials.access_token, 'SlAV32hkKG')
-    self.assertNotEqual(credentials.token_expiry, None)
-    self.assertEqual(credentials.refresh_token, '8xLOxBtZp8')
+    self.assertEqual('SlAV32hkKG', credentials.access_token)
+    self.assertNotEqual(None, credentials.token_expiry)
+    self.assertEqual('8xLOxBtZp8', credentials.refresh_token)
 
   def test_exchange_no_expires_in(self):
     http = HttpMockSequence([
@@ -257,7 +257,7 @@
       ])
 
     credentials = self.flow.step2_exchange('some random code', http)
-    self.assertEqual(credentials.token_expiry, None)
+    self.assertEqual(None, credentials.token_expiry)
 
   def test_exchange_id_token_fail(self):
     http = HttpMockSequence([
@@ -282,7 +282,7 @@
       ])
 
     credentials = self.flow.step2_exchange('some random code', http)
-    self.assertEquals(body, credentials.id_token)
+    self.assertEqual(credentials.id_token, body)
 
 
 if __name__ == '__main__':
diff --git a/tests/test_oauth2client_jwt.py b/tests/test_oauth2client_jwt.py
index 83551c6..dcbb33c 100644
--- a/tests/test_oauth2client_jwt.py
+++ b/tests/test_oauth2client_jwt.py
@@ -100,8 +100,8 @@
     certs = {'foo': public_key }
     audience = 'some_audience_address@testing.gserviceaccount.com'
     contents = crypt.verify_signed_jwt_with_certs(jwt, certs, audience)
-    self.assertEquals('billy bob', contents['user'])
-    self.assertEquals('data', contents['metadata']['meta'])
+    self.assertEqual('billy bob', contents['user'])
+    self.assertEqual('data', contents['metadata']['meta'])
 
   def test_verify_id_token_with_certs_uri(self):
     jwt = self._create_signed_jwt()
@@ -112,8 +112,8 @@
 
     contents = verify_id_token(jwt,
         'some_audience_address@testing.gserviceaccount.com', http)
-    self.assertEquals('billy bob', contents['user'])
-    self.assertEquals('data', contents['metadata']['meta'])
+    self.assertEqual('billy bob', contents['user'])
+    self.assertEqual('data', contents['metadata']['meta'])
 
   def test_verify_id_token_with_certs_uri_fails(self):
     jwt = self._create_signed_jwt()
@@ -195,7 +195,7 @@
       ])
     http = credentials.authorize(http)
     resp, content = http.request('http://example.org')
-    self.assertEquals(content['authorization'], 'OAuth 1/3w')
+    self.assertEqual('Bearer 1/3w', content['Authorization'])
 
 if __name__ == '__main__':
   unittest.main()