chore: blacken (#375)

diff --git a/tests/oauth2/test__client.py b/tests/oauth2/test__client.py
index 6fc4c3b..c415a1f 100644
--- a/tests/oauth2/test__client.py
+++ b/tests/oauth2/test__client.py
@@ -30,42 +30,44 @@
 from google.oauth2 import _client
 
 
-DATA_DIR = os.path.join(os.path.dirname(__file__), '..', 'data')
+DATA_DIR = os.path.join(os.path.dirname(__file__), "..", "data")
 
-with open(os.path.join(DATA_DIR, 'privatekey.pem'), 'rb') as fh:
+with open(os.path.join(DATA_DIR, "privatekey.pem"), "rb") as fh:
     PRIVATE_KEY_BYTES = fh.read()
 
-SIGNER = crypt.RSASigner.from_string(PRIVATE_KEY_BYTES, '1')
+SIGNER = crypt.RSASigner.from_string(PRIVATE_KEY_BYTES, "1")
 
-SCOPES_AS_LIST = ['https://www.googleapis.com/auth/pubsub',
-                  'https://www.googleapis.com/auth/logging.write']
-SCOPES_AS_STRING = ('https://www.googleapis.com/auth/pubsub'
-                    ' https://www.googleapis.com/auth/logging.write')
+SCOPES_AS_LIST = [
+    "https://www.googleapis.com/auth/pubsub",
+    "https://www.googleapis.com/auth/logging.write",
+]
+SCOPES_AS_STRING = (
+    "https://www.googleapis.com/auth/pubsub"
+    " https://www.googleapis.com/auth/logging.write"
+)
 
 
 def test__handle_error_response():
-    response_data = json.dumps({
-        'error': 'help',
-        'error_description': 'I\'m alive'})
+    response_data = json.dumps({"error": "help", "error_description": "I'm alive"})
 
     with pytest.raises(exceptions.RefreshError) as excinfo:
         _client._handle_error_response(response_data)
 
-    assert excinfo.match(r'help: I\'m alive')
+    assert excinfo.match(r"help: I\'m alive")
 
 
 def test__handle_error_response_non_json():
-    response_data = 'Help, I\'m alive'
+    response_data = "Help, I'm alive"
 
     with pytest.raises(exceptions.RefreshError) as excinfo:
         _client._handle_error_response(response_data)
 
-    assert excinfo.match(r'Help, I\'m alive')
+    assert excinfo.match(r"Help, I\'m alive")
 
 
-@mock.patch('google.auth._helpers.utcnow', return_value=datetime.datetime.min)
+@mock.patch("google.auth._helpers.utcnow", return_value=datetime.datetime.min)
 def test__parse_expiry(unused_utcnow):
-    result = _client._parse_expiry({'expires_in': 500})
+    result = _client._parse_expiry({"expires_in": 500})
     assert result == datetime.datetime.min + datetime.timedelta(seconds=500)
 
 
@@ -76,188 +78,214 @@
 def make_request(response_data, status=http_client.OK):
     response = mock.create_autospec(transport.Response, instance=True)
     response.status = status
-    response.data = json.dumps(response_data).encode('utf-8')
+    response.data = json.dumps(response_data).encode("utf-8")
     request = mock.create_autospec(transport.Request)
     request.return_value = response
     return request
 
 
 def test__token_endpoint_request():
-    request = make_request({'test': 'response'})
+    request = make_request({"test": "response"})
 
     result = _client._token_endpoint_request(
-        request, 'http://example.com', {'test': 'params'})
+        request, "http://example.com", {"test": "params"}
+    )
 
     # Check request call
     request.assert_called_with(
-        method='POST',
-        url='http://example.com',
-        headers={'content-type': 'application/x-www-form-urlencoded'},
-        body='test=params')
+        method="POST",
+        url="http://example.com",
+        headers={"content-type": "application/x-www-form-urlencoded"},
+        body="test=params",
+    )
 
     # Check result
-    assert result == {'test': 'response'}
+    assert result == {"test": "response"}
 
 
 def test__token_endpoint_request_error():
     request = make_request({}, status=http_client.BAD_REQUEST)
 
     with pytest.raises(exceptions.RefreshError):
-        _client._token_endpoint_request(request, 'http://example.com', {})
+        _client._token_endpoint_request(request, "http://example.com", {})
 
 
 def test__token_endpoint_request_internal_failure_error():
-    request = make_request({'error': 'internal_failure',
-                            'error_description': 'internal_failure'},
-                           status=http_client.BAD_REQUEST)
+    request = make_request(
+        {"error": "internal_failure", "error_description": "internal_failure"},
+        status=http_client.BAD_REQUEST,
+    )
 
     with pytest.raises(exceptions.RefreshError):
         _client._token_endpoint_request(
-            request, 'http://example.com',
-            {'error': 'internal_failure',
-             'error_description': 'internal_failure'})
+            request,
+            "http://example.com",
+            {"error": "internal_failure", "error_description": "internal_failure"},
+        )
 
 
 def verify_request_params(request, params):
-    request_body = request.call_args[1]['body']
+    request_body = request.call_args[1]["body"]
     request_params = urllib.parse.parse_qs(request_body)
 
     for key, value in six.iteritems(params):
         assert request_params[key][0] == value
 
 
-@mock.patch('google.auth._helpers.utcnow', return_value=datetime.datetime.min)
+@mock.patch("google.auth._helpers.utcnow", return_value=datetime.datetime.min)
 def test_jwt_grant(utcnow):
-    request = make_request({
-        'access_token': 'token',
-        'expires_in': 500,
-        'extra': 'data'})
+    request = make_request(
+        {"access_token": "token", "expires_in": 500, "extra": "data"}
+    )
 
     token, expiry, extra_data = _client.jwt_grant(
-        request, 'http://example.com', 'assertion_value')
+        request, "http://example.com", "assertion_value"
+    )
 
     # Check request call
-    verify_request_params(request, {
-        'grant_type': _client._JWT_GRANT_TYPE,
-        'assertion': 'assertion_value'
-    })
+    verify_request_params(
+        request, {"grant_type": _client._JWT_GRANT_TYPE, "assertion": "assertion_value"}
+    )
 
     # Check result
-    assert token == 'token'
+    assert token == "token"
     assert expiry == utcnow() + datetime.timedelta(seconds=500)
-    assert extra_data['extra'] == 'data'
+    assert extra_data["extra"] == "data"
 
 
 def test_jwt_grant_no_access_token():
-    request = make_request({
-        # No access token.
-        'expires_in': 500,
-        'extra': 'data'})
+    request = make_request(
+        {
+            # No access token.
+            "expires_in": 500,
+            "extra": "data",
+        }
+    )
 
     with pytest.raises(exceptions.RefreshError):
-        _client.jwt_grant(request, 'http://example.com', 'assertion_value')
+        _client.jwt_grant(request, "http://example.com", "assertion_value")
 
 
 def test_id_token_jwt_grant():
     now = _helpers.utcnow()
     id_token_expiry = _helpers.datetime_to_secs(now)
-    id_token = jwt.encode(SIGNER, {'exp': id_token_expiry}).decode('utf-8')
-    request = make_request({
-        'id_token': id_token,
-        'extra': 'data'})
+    id_token = jwt.encode(SIGNER, {"exp": id_token_expiry}).decode("utf-8")
+    request = make_request({"id_token": id_token, "extra": "data"})
 
     token, expiry, extra_data = _client.id_token_jwt_grant(
-        request, 'http://example.com', 'assertion_value')
+        request, "http://example.com", "assertion_value"
+    )
 
     # Check request call
-    verify_request_params(request, {
-        'grant_type': _client._JWT_GRANT_TYPE,
-        'assertion': 'assertion_value'
-    })
+    verify_request_params(
+        request, {"grant_type": _client._JWT_GRANT_TYPE, "assertion": "assertion_value"}
+    )
 
     # Check result
     assert token == id_token
     # JWT does not store microseconds
     now = now.replace(microsecond=0)
     assert expiry == now
-    assert extra_data['extra'] == 'data'
+    assert extra_data["extra"] == "data"
 
 
 def test_id_token_jwt_grant_no_access_token():
-    request = make_request({
-        # No access token.
-        'expires_in': 500,
-        'extra': 'data'})
+    request = make_request(
+        {
+            # No access token.
+            "expires_in": 500,
+            "extra": "data",
+        }
+    )
 
     with pytest.raises(exceptions.RefreshError):
-        _client.id_token_jwt_grant(
-            request, 'http://example.com', 'assertion_value')
+        _client.id_token_jwt_grant(request, "http://example.com", "assertion_value")
 
 
-@mock.patch('google.auth._helpers.utcnow', return_value=datetime.datetime.min)
+@mock.patch("google.auth._helpers.utcnow", return_value=datetime.datetime.min)
 def test_refresh_grant(unused_utcnow):
-    request = make_request({
-        'access_token': 'token',
-        'refresh_token': 'new_refresh_token',
-        'expires_in': 500,
-        'extra': 'data'})
+    request = make_request(
+        {
+            "access_token": "token",
+            "refresh_token": "new_refresh_token",
+            "expires_in": 500,
+            "extra": "data",
+        }
+    )
 
     token, refresh_token, expiry, extra_data = _client.refresh_grant(
-        request, 'http://example.com', 'refresh_token', 'client_id',
-        'client_secret')
+        request, "http://example.com", "refresh_token", "client_id", "client_secret"
+    )
 
     # Check request call
-    verify_request_params(request, {
-        'grant_type': _client._REFRESH_GRANT_TYPE,
-        'refresh_token': 'refresh_token',
-        'client_id': 'client_id',
-        'client_secret': 'client_secret'
-    })
+    verify_request_params(
+        request,
+        {
+            "grant_type": _client._REFRESH_GRANT_TYPE,
+            "refresh_token": "refresh_token",
+            "client_id": "client_id",
+            "client_secret": "client_secret",
+        },
+    )
 
     # Check result
-    assert token == 'token'
-    assert refresh_token == 'new_refresh_token'
+    assert token == "token"
+    assert refresh_token == "new_refresh_token"
     assert expiry == datetime.datetime.min + datetime.timedelta(seconds=500)
-    assert extra_data['extra'] == 'data'
+    assert extra_data["extra"] == "data"
 
 
-@mock.patch('google.auth._helpers.utcnow', return_value=datetime.datetime.min)
+@mock.patch("google.auth._helpers.utcnow", return_value=datetime.datetime.min)
 def test_refresh_grant_with_scopes(unused_utcnow):
-    request = make_request({
-        'access_token': 'token',
-        'refresh_token': 'new_refresh_token',
-        'expires_in': 500,
-        'extra': 'data',
-        'scope': SCOPES_AS_STRING})
+    request = make_request(
+        {
+            "access_token": "token",
+            "refresh_token": "new_refresh_token",
+            "expires_in": 500,
+            "extra": "data",
+            "scope": SCOPES_AS_STRING,
+        }
+    )
 
     token, refresh_token, expiry, extra_data = _client.refresh_grant(
-        request, 'http://example.com', 'refresh_token', 'client_id',
-        'client_secret', SCOPES_AS_LIST)
+        request,
+        "http://example.com",
+        "refresh_token",
+        "client_id",
+        "client_secret",
+        SCOPES_AS_LIST,
+    )
 
     # Check request call.
-    verify_request_params(request, {
-        'grant_type': _client._REFRESH_GRANT_TYPE,
-        'refresh_token': 'refresh_token',
-        'client_id': 'client_id',
-        'client_secret': 'client_secret',
-        'scope': SCOPES_AS_STRING
-    })
+    verify_request_params(
+        request,
+        {
+            "grant_type": _client._REFRESH_GRANT_TYPE,
+            "refresh_token": "refresh_token",
+            "client_id": "client_id",
+            "client_secret": "client_secret",
+            "scope": SCOPES_AS_STRING,
+        },
+    )
 
     # Check result.
-    assert token == 'token'
-    assert refresh_token == 'new_refresh_token'
+    assert token == "token"
+    assert refresh_token == "new_refresh_token"
     assert expiry == datetime.datetime.min + datetime.timedelta(seconds=500)
-    assert extra_data['extra'] == 'data'
+    assert extra_data["extra"] == "data"
 
 
 def test_refresh_grant_no_access_token():
-    request = make_request({
-        # No access token.
-        'refresh_token': 'new_refresh_token',
-        'expires_in': 500,
-        'extra': 'data'})
+    request = make_request(
+        {
+            # No access token.
+            "refresh_token": "new_refresh_token",
+            "expires_in": 500,
+            "extra": "data",
+        }
+    )
 
     with pytest.raises(exceptions.RefreshError):
         _client.refresh_grant(
-            request, 'http://example.com', 'refresh_token', 'client_id',
-            'client_secret')
+            request, "http://example.com", "refresh_token", "client_id", "client_secret"
+        )
diff --git a/tests/oauth2/test_credentials.py b/tests/oauth2/test_credentials.py
index 3231509..8bfdd7e 100644
--- a/tests/oauth2/test_credentials.py
+++ b/tests/oauth2/test_credentials.py
@@ -25,26 +25,29 @@
 from google.oauth2 import credentials
 
 
-DATA_DIR = os.path.join(os.path.dirname(__file__), '..', 'data')
+DATA_DIR = os.path.join(os.path.dirname(__file__), "..", "data")
 
-AUTH_USER_JSON_FILE = os.path.join(DATA_DIR, 'authorized_user.json')
+AUTH_USER_JSON_FILE = os.path.join(DATA_DIR, "authorized_user.json")
 
-with open(AUTH_USER_JSON_FILE, 'r') as fh:
+with open(AUTH_USER_JSON_FILE, "r") as fh:
     AUTH_USER_INFO = json.load(fh)
 
 
 class TestCredentials(object):
-    TOKEN_URI = 'https://example.com/oauth2/token'
-    REFRESH_TOKEN = 'refresh_token'
-    CLIENT_ID = 'client_id'
-    CLIENT_SECRET = 'client_secret'
+    TOKEN_URI = "https://example.com/oauth2/token"
+    REFRESH_TOKEN = "refresh_token"
+    CLIENT_ID = "client_id"
+    CLIENT_SECRET = "client_secret"
 
     @classmethod
     def make_credentials(cls):
         return credentials.Credentials(
-            token=None, refresh_token=cls.REFRESH_TOKEN,
-            token_uri=cls.TOKEN_URI, client_id=cls.CLIENT_ID,
-            client_secret=cls.CLIENT_SECRET)
+            token=None,
+            refresh_token=cls.REFRESH_TOKEN,
+            token_uri=cls.TOKEN_URI,
+            client_id=cls.CLIENT_ID,
+            client_secret=cls.CLIENT_SECRET,
+        )
 
     def test_default_state(self):
         credentials = self.make_credentials()
@@ -59,14 +62,15 @@
         assert credentials.client_id == self.CLIENT_ID
         assert credentials.client_secret == self.CLIENT_SECRET
 
-    @mock.patch('google.oauth2._client.refresh_grant', autospec=True)
+    @mock.patch("google.oauth2._client.refresh_grant", autospec=True)
     @mock.patch(
-        'google.auth._helpers.utcnow',
-        return_value=datetime.datetime.min + _helpers.CLOCK_SKEW)
+        "google.auth._helpers.utcnow",
+        return_value=datetime.datetime.min + _helpers.CLOCK_SKEW,
+    )
     def test_refresh_success(self, unused_utcnow, refresh_grant):
-        token = 'token'
+        token = "token"
         expiry = _helpers.utcnow() + datetime.timedelta(seconds=500)
-        grant_response = {'id_token': mock.sentinel.id_token}
+        grant_response = {"id_token": mock.sentinel.id_token}
         refresh_grant.return_value = (
             # Access token
             token,
@@ -75,7 +79,8 @@
             # Expiry,
             expiry,
             # Extra data
-            grant_response)
+            grant_response,
+        )
 
         request = mock.create_autospec(transport.Request)
         credentials = self.make_credentials()
@@ -85,8 +90,13 @@
 
         # Check jwt grant call.
         refresh_grant.assert_called_with(
-            request, self.TOKEN_URI, self.REFRESH_TOKEN, self.CLIENT_ID,
-            self.CLIENT_SECRET, None)
+            request,
+            self.TOKEN_URI,
+            self.REFRESH_TOKEN,
+            self.CLIENT_ID,
+            self.CLIENT_SECRET,
+            None,
+        )
 
         # Check that the credentials have the token and expiry
         assert credentials.token == token
@@ -99,24 +109,25 @@
 
     def test_refresh_no_refresh_token(self):
         request = mock.create_autospec(transport.Request)
-        credentials_ = credentials.Credentials(
-            token=None, refresh_token=None)
+        credentials_ = credentials.Credentials(token=None, refresh_token=None)
 
-        with pytest.raises(exceptions.RefreshError, match='necessary fields'):
+        with pytest.raises(exceptions.RefreshError, match="necessary fields"):
             credentials_.refresh(request)
 
         request.assert_not_called()
 
-    @mock.patch('google.oauth2._client.refresh_grant', autospec=True)
+    @mock.patch("google.oauth2._client.refresh_grant", autospec=True)
     @mock.patch(
-        'google.auth._helpers.utcnow',
-        return_value=datetime.datetime.min + _helpers.CLOCK_SKEW)
+        "google.auth._helpers.utcnow",
+        return_value=datetime.datetime.min + _helpers.CLOCK_SKEW,
+    )
     def test_credentials_with_scopes_requested_refresh_success(
-            self, unused_utcnow, refresh_grant):
-        scopes = ['email', 'profile']
-        token = 'token'
+        self, unused_utcnow, refresh_grant
+    ):
+        scopes = ["email", "profile"]
+        token = "token"
         expiry = _helpers.utcnow() + datetime.timedelta(seconds=500)
-        grant_response = {'id_token': mock.sentinel.id_token}
+        grant_response = {"id_token": mock.sentinel.id_token}
         refresh_grant.return_value = (
             # Access token
             token,
@@ -125,21 +136,31 @@
             # Expiry,
             expiry,
             # Extra data
-            grant_response)
+            grant_response,
+        )
 
         request = mock.create_autospec(transport.Request)
         creds = credentials.Credentials(
-            token=None, refresh_token=self.REFRESH_TOKEN,
-            token_uri=self.TOKEN_URI, client_id=self.CLIENT_ID,
-            client_secret=self.CLIENT_SECRET, scopes=scopes)
+            token=None,
+            refresh_token=self.REFRESH_TOKEN,
+            token_uri=self.TOKEN_URI,
+            client_id=self.CLIENT_ID,
+            client_secret=self.CLIENT_SECRET,
+            scopes=scopes,
+        )
 
         # Refresh credentials
         creds.refresh(request)
 
         # Check jwt grant call.
         refresh_grant.assert_called_with(
-            request, self.TOKEN_URI, self.REFRESH_TOKEN, self.CLIENT_ID,
-            self.CLIENT_SECRET, scopes)
+            request,
+            self.TOKEN_URI,
+            self.REFRESH_TOKEN,
+            self.CLIENT_ID,
+            self.CLIENT_SECRET,
+            scopes,
+        )
 
         # Check that the credentials have the token and expiry
         assert creds.token == token
@@ -151,17 +172,21 @@
         # expired.)
         assert creds.valid
 
-    @mock.patch('google.oauth2._client.refresh_grant', autospec=True)
+    @mock.patch("google.oauth2._client.refresh_grant", autospec=True)
     @mock.patch(
-        'google.auth._helpers.utcnow',
-        return_value=datetime.datetime.min + _helpers.CLOCK_SKEW)
+        "google.auth._helpers.utcnow",
+        return_value=datetime.datetime.min + _helpers.CLOCK_SKEW,
+    )
     def test_credentials_with_scopes_returned_refresh_success(
-            self, unused_utcnow, refresh_grant):
-        scopes = ['email', 'profile']
-        token = 'token'
+        self, unused_utcnow, refresh_grant
+    ):
+        scopes = ["email", "profile"]
+        token = "token"
         expiry = _helpers.utcnow() + datetime.timedelta(seconds=500)
-        grant_response = {'id_token': mock.sentinel.id_token,
-                          'scopes': ' '.join(scopes)}
+        grant_response = {
+            "id_token": mock.sentinel.id_token,
+            "scopes": " ".join(scopes),
+        }
         refresh_grant.return_value = (
             # Access token
             token,
@@ -170,21 +195,31 @@
             # Expiry,
             expiry,
             # Extra data
-            grant_response)
+            grant_response,
+        )
 
         request = mock.create_autospec(transport.Request)
         creds = credentials.Credentials(
-            token=None, refresh_token=self.REFRESH_TOKEN,
-            token_uri=self.TOKEN_URI, client_id=self.CLIENT_ID,
-            client_secret=self.CLIENT_SECRET, scopes=scopes)
+            token=None,
+            refresh_token=self.REFRESH_TOKEN,
+            token_uri=self.TOKEN_URI,
+            client_id=self.CLIENT_ID,
+            client_secret=self.CLIENT_SECRET,
+            scopes=scopes,
+        )
 
         # Refresh credentials
         creds.refresh(request)
 
         # Check jwt grant call.
         refresh_grant.assert_called_with(
-            request, self.TOKEN_URI, self.REFRESH_TOKEN, self.CLIENT_ID,
-            self.CLIENT_SECRET, scopes)
+            request,
+            self.TOKEN_URI,
+            self.REFRESH_TOKEN,
+            self.CLIENT_ID,
+            self.CLIENT_SECRET,
+            scopes,
+        )
 
         # Check that the credentials have the token and expiry
         assert creds.token == token
@@ -196,18 +231,22 @@
         # expired.)
         assert creds.valid
 
-    @mock.patch('google.oauth2._client.refresh_grant', autospec=True)
+    @mock.patch("google.oauth2._client.refresh_grant", autospec=True)
     @mock.patch(
-        'google.auth._helpers.utcnow',
-        return_value=datetime.datetime.min + _helpers.CLOCK_SKEW)
+        "google.auth._helpers.utcnow",
+        return_value=datetime.datetime.min + _helpers.CLOCK_SKEW,
+    )
     def test_credentials_with_scopes_refresh_failure_raises_refresh_error(
-            self, unused_utcnow, refresh_grant):
-        scopes = ['email', 'profile']
-        scopes_returned = ['email']
-        token = 'token'
+        self, unused_utcnow, refresh_grant
+    ):
+        scopes = ["email", "profile"]
+        scopes_returned = ["email"]
+        token = "token"
         expiry = _helpers.utcnow() + datetime.timedelta(seconds=500)
-        grant_response = {'id_token': mock.sentinel.id_token,
-                          'scopes': ' '.join(scopes_returned)}
+        grant_response = {
+            "id_token": mock.sentinel.id_token,
+            "scopes": " ".join(scopes_returned),
+        }
         refresh_grant.return_value = (
             # Access token
             token,
@@ -216,23 +255,34 @@
             # Expiry,
             expiry,
             # Extra data
-            grant_response)
+            grant_response,
+        )
 
         request = mock.create_autospec(transport.Request)
         creds = credentials.Credentials(
-            token=None, refresh_token=self.REFRESH_TOKEN,
-            token_uri=self.TOKEN_URI, client_id=self.CLIENT_ID,
-            client_secret=self.CLIENT_SECRET, scopes=scopes)
+            token=None,
+            refresh_token=self.REFRESH_TOKEN,
+            token_uri=self.TOKEN_URI,
+            client_id=self.CLIENT_ID,
+            client_secret=self.CLIENT_SECRET,
+            scopes=scopes,
+        )
 
         # Refresh credentials
-        with pytest.raises(exceptions.RefreshError,
-                           match='Not all requested scopes were granted'):
+        with pytest.raises(
+            exceptions.RefreshError, match="Not all requested scopes were granted"
+        ):
             creds.refresh(request)
 
         # Check jwt grant call.
         refresh_grant.assert_called_with(
-            request, self.TOKEN_URI, self.REFRESH_TOKEN, self.CLIENT_ID,
-            self.CLIENT_SECRET, scopes)
+            request,
+            self.TOKEN_URI,
+            self.REFRESH_TOKEN,
+            self.CLIENT_ID,
+            self.CLIENT_SECRET,
+            scopes,
+        )
 
         # Check that the credentials have the token and expiry
         assert creds.token == token
@@ -248,37 +298,36 @@
         info = AUTH_USER_INFO.copy()
 
         creds = credentials.Credentials.from_authorized_user_info(info)
-        assert creds.client_secret == info['client_secret']
-        assert creds.client_id == info['client_id']
-        assert creds.refresh_token == info['refresh_token']
+        assert creds.client_secret == info["client_secret"]
+        assert creds.client_id == info["client_id"]
+        assert creds.refresh_token == info["refresh_token"]
         assert creds.token_uri == credentials._GOOGLE_OAUTH2_TOKEN_ENDPOINT
         assert creds.scopes is None
 
-        scopes = ['email', 'profile']
-        creds = credentials.Credentials.from_authorized_user_info(
-            info, scopes)
-        assert creds.client_secret == info['client_secret']
-        assert creds.client_id == info['client_id']
-        assert creds.refresh_token == info['refresh_token']
+        scopes = ["email", "profile"]
+        creds = credentials.Credentials.from_authorized_user_info(info, scopes)
+        assert creds.client_secret == info["client_secret"]
+        assert creds.client_id == info["client_id"]
+        assert creds.refresh_token == info["refresh_token"]
         assert creds.token_uri == credentials._GOOGLE_OAUTH2_TOKEN_ENDPOINT
         assert creds.scopes == scopes
 
     def test_from_authorized_user_file(self):
         info = AUTH_USER_INFO.copy()
 
-        creds = credentials.Credentials.from_authorized_user_file(
-            AUTH_USER_JSON_FILE)
-        assert creds.client_secret == info['client_secret']
-        assert creds.client_id == info['client_id']
-        assert creds.refresh_token == info['refresh_token']
+        creds = credentials.Credentials.from_authorized_user_file(AUTH_USER_JSON_FILE)
+        assert creds.client_secret == info["client_secret"]
+        assert creds.client_id == info["client_id"]
+        assert creds.refresh_token == info["refresh_token"]
         assert creds.token_uri == credentials._GOOGLE_OAUTH2_TOKEN_ENDPOINT
         assert creds.scopes is None
 
-        scopes = ['email', 'profile']
+        scopes = ["email", "profile"]
         creds = credentials.Credentials.from_authorized_user_file(
-            AUTH_USER_JSON_FILE, scopes)
-        assert creds.client_secret == info['client_secret']
-        assert creds.client_id == info['client_id']
-        assert creds.refresh_token == info['refresh_token']
+            AUTH_USER_JSON_FILE, scopes
+        )
+        assert creds.client_secret == info["client_secret"]
+        assert creds.client_id == info["client_id"]
+        assert creds.refresh_token == info["refresh_token"]
         assert creds.token_uri == credentials._GOOGLE_OAUTH2_TOKEN_ENDPOINT
         assert creds.scopes == scopes
diff --git a/tests/oauth2/test_id_token.py b/tests/oauth2/test_id_token.py
index 360f92f..980a8e9 100644
--- a/tests/oauth2/test_id_token.py
+++ b/tests/oauth2/test_id_token.py
@@ -27,7 +27,7 @@
     response.status = status
 
     if data is not None:
-        response.data = json.dumps(data).encode('utf-8')
+        response.data = json.dumps(data).encode("utf-8")
 
     request = mock.create_autospec(transport.Request)
     request.return_value = response
@@ -35,12 +35,12 @@
 
 
 def test__fetch_certs_success():
-    certs = {'1': 'cert'}
+    certs = {"1": "cert"}
     request = make_request(200, certs)
 
     returned_certs = id_token._fetch_certs(request, mock.sentinel.cert_url)
 
-    request.assert_called_once_with(mock.sentinel.cert_url, method='GET')
+    request.assert_called_once_with(mock.sentinel.cert_url, method="GET")
     assert returned_certs == certs
 
 
@@ -50,66 +50,67 @@
     with pytest.raises(exceptions.TransportError):
         id_token._fetch_certs(request, mock.sentinel.cert_url)
 
-    request.assert_called_once_with(mock.sentinel.cert_url, method='GET')
+    request.assert_called_once_with(mock.sentinel.cert_url, method="GET")
 
 
-@mock.patch('google.auth.jwt.decode', autospec=True)
-@mock.patch('google.oauth2.id_token._fetch_certs', autospec=True)
+@mock.patch("google.auth.jwt.decode", autospec=True)
+@mock.patch("google.oauth2.id_token._fetch_certs", autospec=True)
 def test_verify_token(_fetch_certs, decode):
     result = id_token.verify_token(mock.sentinel.token, mock.sentinel.request)
 
     assert result == decode.return_value
     _fetch_certs.assert_called_once_with(
-        mock.sentinel.request, id_token._GOOGLE_OAUTH2_CERTS_URL)
+        mock.sentinel.request, id_token._GOOGLE_OAUTH2_CERTS_URL
+    )
     decode.assert_called_once_with(
-        mock.sentinel.token,
-        certs=_fetch_certs.return_value,
-        audience=None)
+        mock.sentinel.token, certs=_fetch_certs.return_value, audience=None
+    )
 
 
-@mock.patch('google.auth.jwt.decode', autospec=True)
-@mock.patch('google.oauth2.id_token._fetch_certs', autospec=True)
+@mock.patch("google.auth.jwt.decode", autospec=True)
+@mock.patch("google.oauth2.id_token._fetch_certs", autospec=True)
 def test_verify_token_args(_fetch_certs, decode):
     result = id_token.verify_token(
         mock.sentinel.token,
         mock.sentinel.request,
         audience=mock.sentinel.audience,
-        certs_url=mock.sentinel.certs_url)
+        certs_url=mock.sentinel.certs_url,
+    )
 
     assert result == decode.return_value
-    _fetch_certs.assert_called_once_with(
-        mock.sentinel.request, mock.sentinel.certs_url)
+    _fetch_certs.assert_called_once_with(mock.sentinel.request, mock.sentinel.certs_url)
     decode.assert_called_once_with(
         mock.sentinel.token,
         certs=_fetch_certs.return_value,
-        audience=mock.sentinel.audience)
+        audience=mock.sentinel.audience,
+    )
 
 
-@mock.patch('google.oauth2.id_token.verify_token', autospec=True)
+@mock.patch("google.oauth2.id_token.verify_token", autospec=True)
 def test_verify_oauth2_token(verify_token):
     result = id_token.verify_oauth2_token(
-        mock.sentinel.token,
-        mock.sentinel.request,
-        audience=mock.sentinel.audience)
+        mock.sentinel.token, mock.sentinel.request, audience=mock.sentinel.audience
+    )
 
     assert result == verify_token.return_value
     verify_token.assert_called_once_with(
         mock.sentinel.token,
         mock.sentinel.request,
         audience=mock.sentinel.audience,
-        certs_url=id_token._GOOGLE_OAUTH2_CERTS_URL)
+        certs_url=id_token._GOOGLE_OAUTH2_CERTS_URL,
+    )
 
 
-@mock.patch('google.oauth2.id_token.verify_token', autospec=True)
+@mock.patch("google.oauth2.id_token.verify_token", autospec=True)
 def test_verify_firebase_token(verify_token):
     result = id_token.verify_firebase_token(
-        mock.sentinel.token,
-        mock.sentinel.request,
-        audience=mock.sentinel.audience)
+        mock.sentinel.token, mock.sentinel.request, audience=mock.sentinel.audience
+    )
 
     assert result == verify_token.return_value
     verify_token.assert_called_once_with(
         mock.sentinel.token,
         mock.sentinel.request,
         audience=mock.sentinel.audience,
-        certs_url=id_token._GOOGLE_APIS_CERTS_URL)
+        certs_url=id_token._GOOGLE_APIS_CERTS_URL,
+    )
diff --git a/tests/oauth2/test_service_account.py b/tests/oauth2/test_service_account.py
index 54ac0f5..0f9d460 100644
--- a/tests/oauth2/test_service_account.py
+++ b/tests/oauth2/test_service_account.py
@@ -25,58 +25,58 @@
 from google.oauth2 import service_account
 
 
-DATA_DIR = os.path.join(os.path.dirname(__file__), '..', 'data')
+DATA_DIR = os.path.join(os.path.dirname(__file__), "..", "data")
 
-with open(os.path.join(DATA_DIR, 'privatekey.pem'), 'rb') as fh:
+with open(os.path.join(DATA_DIR, "privatekey.pem"), "rb") as fh:
     PRIVATE_KEY_BYTES = fh.read()
 
-with open(os.path.join(DATA_DIR, 'public_cert.pem'), 'rb') as fh:
+with open(os.path.join(DATA_DIR, "public_cert.pem"), "rb") as fh:
     PUBLIC_CERT_BYTES = fh.read()
 
-with open(os.path.join(DATA_DIR, 'other_cert.pem'), 'rb') as fh:
+with open(os.path.join(DATA_DIR, "other_cert.pem"), "rb") as fh:
     OTHER_CERT_BYTES = fh.read()
 
-SERVICE_ACCOUNT_JSON_FILE = os.path.join(DATA_DIR, 'service_account.json')
+SERVICE_ACCOUNT_JSON_FILE = os.path.join(DATA_DIR, "service_account.json")
 
-with open(SERVICE_ACCOUNT_JSON_FILE, 'r') as fh:
+with open(SERVICE_ACCOUNT_JSON_FILE, "r") as fh:
     SERVICE_ACCOUNT_INFO = json.load(fh)
 
-SIGNER = crypt.RSASigner.from_string(PRIVATE_KEY_BYTES, '1')
+SIGNER = crypt.RSASigner.from_string(PRIVATE_KEY_BYTES, "1")
 
 
 class TestCredentials(object):
-    SERVICE_ACCOUNT_EMAIL = 'service-account@example.com'
-    TOKEN_URI = 'https://example.com/oauth2/token'
+    SERVICE_ACCOUNT_EMAIL = "service-account@example.com"
+    TOKEN_URI = "https://example.com/oauth2/token"
 
     @classmethod
     def make_credentials(cls):
         return service_account.Credentials(
-            SIGNER, cls.SERVICE_ACCOUNT_EMAIL, cls.TOKEN_URI)
+            SIGNER, cls.SERVICE_ACCOUNT_EMAIL, cls.TOKEN_URI
+        )
 
     def test_from_service_account_info(self):
         credentials = service_account.Credentials.from_service_account_info(
-            SERVICE_ACCOUNT_INFO)
+            SERVICE_ACCOUNT_INFO
+        )
 
-        assert (credentials._signer.key_id ==
-                SERVICE_ACCOUNT_INFO['private_key_id'])
-        assert (credentials.service_account_email ==
-                SERVICE_ACCOUNT_INFO['client_email'])
-        assert credentials._token_uri == SERVICE_ACCOUNT_INFO['token_uri']
+        assert credentials._signer.key_id == SERVICE_ACCOUNT_INFO["private_key_id"]
+        assert credentials.service_account_email == SERVICE_ACCOUNT_INFO["client_email"]
+        assert credentials._token_uri == SERVICE_ACCOUNT_INFO["token_uri"]
 
     def test_from_service_account_info_args(self):
         info = SERVICE_ACCOUNT_INFO.copy()
-        scopes = ['email', 'profile']
-        subject = 'subject'
-        additional_claims = {'meta': 'data'}
+        scopes = ["email", "profile"]
+        subject = "subject"
+        additional_claims = {"meta": "data"}
 
         credentials = service_account.Credentials.from_service_account_info(
-            info, scopes=scopes, subject=subject,
-            additional_claims=additional_claims)
+            info, scopes=scopes, subject=subject, additional_claims=additional_claims
+        )
 
-        assert credentials.service_account_email == info['client_email']
-        assert credentials.project_id == info['project_id']
-        assert credentials._signer.key_id == info['private_key_id']
-        assert credentials._token_uri == info['token_uri']
+        assert credentials.service_account_email == info["client_email"]
+        assert credentials.project_id == info["project_id"]
+        assert credentials._signer.key_id == info["private_key_id"]
+        assert credentials._token_uri == info["token_uri"]
         assert credentials._scopes == scopes
         assert credentials._subject == subject
         assert credentials._additional_claims == additional_claims
@@ -85,27 +85,31 @@
         info = SERVICE_ACCOUNT_INFO.copy()
 
         credentials = service_account.Credentials.from_service_account_file(
-            SERVICE_ACCOUNT_JSON_FILE)
+            SERVICE_ACCOUNT_JSON_FILE
+        )
 
-        assert credentials.service_account_email == info['client_email']
-        assert credentials.project_id == info['project_id']
-        assert credentials._signer.key_id == info['private_key_id']
-        assert credentials._token_uri == info['token_uri']
+        assert credentials.service_account_email == info["client_email"]
+        assert credentials.project_id == info["project_id"]
+        assert credentials._signer.key_id == info["private_key_id"]
+        assert credentials._token_uri == info["token_uri"]
 
     def test_from_service_account_file_args(self):
         info = SERVICE_ACCOUNT_INFO.copy()
-        scopes = ['email', 'profile']
-        subject = 'subject'
-        additional_claims = {'meta': 'data'}
+        scopes = ["email", "profile"]
+        subject = "subject"
+        additional_claims = {"meta": "data"}
 
         credentials = service_account.Credentials.from_service_account_file(
-            SERVICE_ACCOUNT_JSON_FILE, subject=subject,
-            scopes=scopes, additional_claims=additional_claims)
+            SERVICE_ACCOUNT_JSON_FILE,
+            subject=subject,
+            scopes=scopes,
+            additional_claims=additional_claims,
+        )
 
-        assert credentials.service_account_email == info['client_email']
-        assert credentials.project_id == info['project_id']
-        assert credentials._signer.key_id == info['private_key_id']
-        assert credentials._token_uri == info['token_uri']
+        assert credentials.service_account_email == info["client_email"]
+        assert credentials.project_id == info["project_id"]
+        assert credentials._signer.key_id == info["private_key_id"]
+        assert credentials._token_uri == info["token_uri"]
         assert credentials._scopes == scopes
         assert credentials._subject == subject
         assert credentials._additional_claims == additional_claims
@@ -120,7 +124,7 @@
 
     def test_sign_bytes(self):
         credentials = self.make_credentials()
-        to_sign = b'123'
+        to_sign = b"123"
         signature = credentials.sign_bytes(to_sign)
         assert crypt.verify_signature(to_sign, signature, PUBLIC_CERT_BYTES)
 
@@ -134,46 +138,47 @@
 
     def test_create_scoped(self):
         credentials = self.make_credentials()
-        scopes = ['email', 'profile']
+        scopes = ["email", "profile"]
         credentials = credentials.with_scopes(scopes)
         assert credentials._scopes == scopes
 
     def test_with_claims(self):
         credentials = self.make_credentials()
-        new_credentials = credentials.with_claims({'meep': 'moop'})
-        assert new_credentials._additional_claims == {'meep': 'moop'}
+        new_credentials = credentials.with_claims({"meep": "moop"})
+        assert new_credentials._additional_claims == {"meep": "moop"}
 
     def test__make_authorization_grant_assertion(self):
         credentials = self.make_credentials()
         token = credentials._make_authorization_grant_assertion()
         payload = jwt.decode(token, PUBLIC_CERT_BYTES)
-        assert payload['iss'] == self.SERVICE_ACCOUNT_EMAIL
-        assert payload['aud'] == self.TOKEN_URI
+        assert payload["iss"] == self.SERVICE_ACCOUNT_EMAIL
+        assert payload["aud"] == self.TOKEN_URI
 
     def test__make_authorization_grant_assertion_scoped(self):
         credentials = self.make_credentials()
-        scopes = ['email', 'profile']
+        scopes = ["email", "profile"]
         credentials = credentials.with_scopes(scopes)
         token = credentials._make_authorization_grant_assertion()
         payload = jwt.decode(token, PUBLIC_CERT_BYTES)
-        assert payload['scope'] == 'email profile'
+        assert payload["scope"] == "email profile"
 
     def test__make_authorization_grant_assertion_subject(self):
         credentials = self.make_credentials()
-        subject = 'user@example.com'
+        subject = "user@example.com"
         credentials = credentials.with_subject(subject)
         token = credentials._make_authorization_grant_assertion()
         payload = jwt.decode(token, PUBLIC_CERT_BYTES)
-        assert payload['sub'] == subject
+        assert payload["sub"] == subject
 
-    @mock.patch('google.oauth2._client.jwt_grant', autospec=True)
+    @mock.patch("google.oauth2._client.jwt_grant", autospec=True)
     def test_refresh_success(self, jwt_grant):
         credentials = self.make_credentials()
-        token = 'token'
+        token = "token"
         jwt_grant.return_value = (
             token,
             _helpers.utcnow() + datetime.timedelta(seconds=500),
-            {})
+            {},
+        )
         request = mock.create_autospec(transport.Request, instance=True)
 
         # Refresh credentials
@@ -196,20 +201,22 @@
         # expired)
         assert credentials.valid
 
-    @mock.patch('google.oauth2._client.jwt_grant', autospec=True)
+    @mock.patch("google.oauth2._client.jwt_grant", autospec=True)
     def test_before_request_refreshes(self, jwt_grant):
         credentials = self.make_credentials()
-        token = 'token'
+        token = "token"
         jwt_grant.return_value = (
-            token, _helpers.utcnow() + datetime.timedelta(seconds=500), None)
+            token,
+            _helpers.utcnow() + datetime.timedelta(seconds=500),
+            None,
+        )
         request = mock.create_autospec(transport.Request, instance=True)
 
         # Credentials should start as invalid
         assert not credentials.valid
 
         # before_request should cause a refresh
-        credentials.before_request(
-            request, 'GET', 'http://example.com?a=1#3', {})
+        credentials.before_request(request, "GET", "http://example.com?a=1#3", {})
 
         # The refresh endpoint should've been called.
         assert jwt_grant.called
@@ -219,40 +226,36 @@
 
 
 class TestIDTokenCredentials(object):
-    SERVICE_ACCOUNT_EMAIL = 'service-account@example.com'
-    TOKEN_URI = 'https://example.com/oauth2/token'
-    TARGET_AUDIENCE = 'https://example.com'
+    SERVICE_ACCOUNT_EMAIL = "service-account@example.com"
+    TOKEN_URI = "https://example.com/oauth2/token"
+    TARGET_AUDIENCE = "https://example.com"
 
     @classmethod
     def make_credentials(cls):
         return service_account.IDTokenCredentials(
-            SIGNER, cls.SERVICE_ACCOUNT_EMAIL, cls.TOKEN_URI,
-            cls.TARGET_AUDIENCE)
+            SIGNER, cls.SERVICE_ACCOUNT_EMAIL, cls.TOKEN_URI, cls.TARGET_AUDIENCE
+        )
 
     def test_from_service_account_info(self):
-        credentials = (
-            service_account.IDTokenCredentials.from_service_account_info(
-                SERVICE_ACCOUNT_INFO,
-                target_audience=self.TARGET_AUDIENCE))
+        credentials = service_account.IDTokenCredentials.from_service_account_info(
+            SERVICE_ACCOUNT_INFO, target_audience=self.TARGET_AUDIENCE
+        )
 
-        assert (credentials._signer.key_id ==
-                SERVICE_ACCOUNT_INFO['private_key_id'])
-        assert (credentials.service_account_email ==
-                SERVICE_ACCOUNT_INFO['client_email'])
-        assert credentials._token_uri == SERVICE_ACCOUNT_INFO['token_uri']
+        assert credentials._signer.key_id == SERVICE_ACCOUNT_INFO["private_key_id"]
+        assert credentials.service_account_email == SERVICE_ACCOUNT_INFO["client_email"]
+        assert credentials._token_uri == SERVICE_ACCOUNT_INFO["token_uri"]
         assert credentials._target_audience == self.TARGET_AUDIENCE
 
     def test_from_service_account_file(self):
         info = SERVICE_ACCOUNT_INFO.copy()
 
-        credentials = (
-                service_account.IDTokenCredentials.from_service_account_file(
-                    SERVICE_ACCOUNT_JSON_FILE,
-                    target_audience=self.TARGET_AUDIENCE))
+        credentials = service_account.IDTokenCredentials.from_service_account_file(
+            SERVICE_ACCOUNT_JSON_FILE, target_audience=self.TARGET_AUDIENCE
+        )
 
-        assert credentials.service_account_email == info['client_email']
-        assert credentials._signer.key_id == info['private_key_id']
-        assert credentials._token_uri == info['token_uri']
+        assert credentials.service_account_email == info["client_email"]
+        assert credentials._signer.key_id == info["private_key_id"]
+        assert credentials._token_uri == info["token_uri"]
         assert credentials._target_audience == self.TARGET_AUDIENCE
 
     def test_default_state(self):
@@ -263,7 +266,7 @@
 
     def test_sign_bytes(self):
         credentials = self.make_credentials()
-        to_sign = b'123'
+        to_sign = b"123"
         signature = credentials.sign_bytes(to_sign)
         assert crypt.verify_signature(to_sign, signature, PUBLIC_CERT_BYTES)
 
@@ -277,26 +280,26 @@
 
     def test_with_target_audience(self):
         credentials = self.make_credentials()
-        new_credentials = credentials.with_target_audience(
-            'https://new.example.com')
-        assert new_credentials._target_audience == 'https://new.example.com'
+        new_credentials = credentials.with_target_audience("https://new.example.com")
+        assert new_credentials._target_audience == "https://new.example.com"
 
     def test__make_authorization_grant_assertion(self):
         credentials = self.make_credentials()
         token = credentials._make_authorization_grant_assertion()
         payload = jwt.decode(token, PUBLIC_CERT_BYTES)
-        assert payload['iss'] == self.SERVICE_ACCOUNT_EMAIL
-        assert payload['aud'] == self.TOKEN_URI
-        assert payload['target_audience'] == self.TARGET_AUDIENCE
+        assert payload["iss"] == self.SERVICE_ACCOUNT_EMAIL
+        assert payload["aud"] == self.TOKEN_URI
+        assert payload["target_audience"] == self.TARGET_AUDIENCE
 
-    @mock.patch('google.oauth2._client.id_token_jwt_grant', autospec=True)
+    @mock.patch("google.oauth2._client.id_token_jwt_grant", autospec=True)
     def test_refresh_success(self, id_token_jwt_grant):
         credentials = self.make_credentials()
-        token = 'token'
+        token = "token"
         id_token_jwt_grant.return_value = (
             token,
             _helpers.utcnow() + datetime.timedelta(seconds=500),
-            {})
+            {},
+        )
         request = mock.create_autospec(transport.Request, instance=True)
 
         # Refresh credentials
@@ -319,20 +322,22 @@
         # expired)
         assert credentials.valid
 
-    @mock.patch('google.oauth2._client.id_token_jwt_grant', autospec=True)
+    @mock.patch("google.oauth2._client.id_token_jwt_grant", autospec=True)
     def test_before_request_refreshes(self, id_token_jwt_grant):
         credentials = self.make_credentials()
-        token = 'token'
+        token = "token"
         id_token_jwt_grant.return_value = (
-            token, _helpers.utcnow() + datetime.timedelta(seconds=500), None)
+            token,
+            _helpers.utcnow() + datetime.timedelta(seconds=500),
+            None,
+        )
         request = mock.create_autospec(transport.Request, instance=True)
 
         # Credentials should start as invalid
         assert not credentials.valid
 
         # before_request should cause a refresh
-        credentials.before_request(
-            request, 'GET', 'http://example.com?a=1#3', {})
+        credentials.before_request(request, "GET", "http://example.com?a=1#3", {})
 
         # The refresh endpoint should've been called.
         assert id_token_jwt_grant.called