Allowing datastore system test to run on emulator with no connection.

Currently, the GOOGLE_APPLICATION_CREDENTIALS is used and an access
token is minted even though requests to the emulator require no
authentication.

Author: dhermes

CONTRIBUTING.rst

@@ -233,7 +233,8 @@ Running System Tests
    $ DATASTORE_HOST=http://localhost:8471 \
    >   DATASTORE_DATASET=gcloud-settings-app-id \
    >   GCLOUD_NO_PRINT=true \
-   >   python system_tests/run_system_test.py --package=datastore
+   >   python system_tests/run_system_test.py \
+   >   --package=datastore --ignore-requirements
 
   and after completion stop the emulator::
 

system_tests/datastore.py

@@ -16,6 +16,7 @@
 import os
 import time
 
+import httplib2
 import unittest2
 
 from gcloud._helpers import UTC
@@ -44,6 +45,18 @@ class Config(object):
     CLIENT = None
 
 
+class _EmulatorCreds(object):
+    """A mock credential object.
+
+    Used to avoid unnecessary token refreshing or reliance on the network
+    while an emulator is running.
+    """
+
+    @staticmethod
+    def create_scoped_required():
+        return False
+
+
 def clone_client(client):
     # Fool the Client constructor to avoid creating a new connection.
     cloned_client = datastore.Client(project=client.project,
@@ -58,8 +71,12 @@ def setUpModule():
         client_mod.DATASET = TESTS_DATASET
         Config.CLIENT = datastore.Client(namespace=TEST_NAMESPACE)
     else:
+        credentials = _EmulatorCreds()
+        http = httplib2.Http()  # Un-authorized.
         Config.CLIENT = datastore.Client(project=EMULATOR_DATASET,
-                                         namespace=TEST_NAMESPACE)
+                                         namespace=TEST_NAMESPACE,
+                                         credentials=credentials,
+                                         http=http)
 
 
 class TestDatastore(unittest2.TestCase):

system_tests/run_system_test.py

@@ -45,13 +45,18 @@ def get_parser():
     parser.add_argument('--package', dest='package',
                         choices=REQUIREMENTS.keys(),
                         default='datastore', help='Package to be tested.')
+    parser.add_argument(
+        '--ignore-requirements',
+        dest='ignore_requirements', action='store_true',
+        help='Ignore the credentials requirement for the test.')
     return parser
 
 
-def run_module_tests(module_name):
-    # Make sure environ is set before running test.
-    requirements = REQUIREMENTS[module_name]
-    system_test_utils.check_environ(*requirements)
+def run_module_tests(module_name, ignore_requirements=False):
+    if not ignore_requirements:
+        # Make sure environ is set before running test.
+        requirements = REQUIREMENTS[module_name]
+        system_test_utils.check_environ(*requirements)
 
     suite = unittest2.TestSuite()
     test_mod = TEST_MODULES[module_name]
@@ -68,7 +73,8 @@ def run_module_tests(module_name):
 def main():
     parser = get_parser()
     args = parser.parse_args()
-    run_module_tests(args.package)
+    run_module_tests(args.package,
+                     ignore_requirements=args.ignore_requirements)
 
 
 if __name__ == '__main__':