Fix coverage.

core/unit_tests/test__helpers.py

@@ -644,6 +644,33 @@ def test_it(self):
         secure_authorized_channel.assert_called_once_with(
             credentials, mock.ANY, expected_target, options=expected_options)
 
+    def test_extra_options(self):
+        from six.moves import http_client
+
+        credentials = object()
+        host = 'HOST'
+        user_agent = 'USER_AGENT'
+        extra_options = (('some', 'option'),)
+
+        secure_authorized_channel_patch = mock.patch(
+            'google.auth.transport.grpc.secure_authorized_channel',
+            autospec=True)
+
+        with secure_authorized_channel_patch as secure_authorized_channel:
+            result = self._call_fut(credentials, user_agent, host,
+                                    extra_options)
+
+        self.assertIs(result, secure_authorized_channel.return_value)
+
+        expected_target = '%s:%d' % (host, http_client.HTTPS_PORT)
+        expected_options = (
+            ('grpc.primary_user_agent', user_agent),
+            extra_options[0],
+        )
+
+        secure_authorized_channel.assert_called_once_with(
+            credentials, mock.ANY, expected_target, options=expected_options)
+
 
 class Test_make_secure_stub(unittest.TestCase):