message: Better documentation on the use of pytestmark
diff: @@ -17,6 +17,10 @@ from xain.grpc import (
  from xain.grpc.coordinator import Coordinator, Participants, monitor_heartbeats
  from xain.grpc.participant import heartbeat
  +# Some grpc tests fail on macos.
  +# `pytestmark` when defined on a module will mark all tests in that module.
  +# For more information check
  +# http://doc.pytest.org/en/latest/skipping.html#skip-all-test-functions-of-a-class-or-module
  if sys.platform == "darwin":
  pytestmark = pytest.mark.xfail(reason="some grpc tests fail on macos")
  