Implement support for registry integration tests via py.test

This change implements support for registry integration tests using the new py.test-based live server test fixture. We can now parametrize the protocols we use (in prep for V2_2), and it makes the code *much* cleaner and less hacky.

Note that moving the vast majority of the tests over from the existing impl will come as a followup PR

test/registry/registry_tests.py

@@ -0,0 +1,35 @@
+from test.fixtures import *
+from test.registry.liveserverfixture import *
+from test.registry.fixtures import *
+from test.registry.protocol_fixtures import *
+
+from test.registry.protocols import Failures
+
+
+def test_basic_push_pull(pusher, puller, basic_images, liveserver_session, app_reloader):
+  """ Test: Basic push and pull of an image to a new repository. """
+  credentials = ('devtable', 'password')
+
+  # Push a new repository.
+  pusher.push(liveserver_session, 'devtable', 'newrepo', 'latest', basic_images,
+              credentials=credentials)
+
+  # Pull the repository to verify.
+  puller.pull(liveserver_session, 'devtable', 'newrepo', 'latest', basic_images,
+              credentials=credentials)
+
+
+def test_push_invalid_credentials(pusher, basic_images, liveserver_session, app_reloader):
+  """ Test: Ensure we get auth errors when trying to push with invalid credentials. """
+  invalid_credentials = ('devtable', 'notcorrectpassword')
+
+  pusher.push(liveserver_session, 'devtable', 'newrepo', 'latest', basic_images,
+              credentials=invalid_credentials, expected_failure=Failures.UNAUTHENTICATED)
+
+
+def test_pull_invalid_credentials(puller, basic_images, liveserver_session, app_reloader):
+  """ Test: Ensure we get auth errors when trying to pull with invalid credentials. """
+  invalid_credentials = ('devtable', 'notcorrectpassword')
+
+  puller.pull(liveserver_session, 'devtable', 'newrepo', 'latest', basic_images,
+              credentials=invalid_credentials, expected_failure=Failures.UNAUTHENTICATED)