Cli test

This Pull Request  builds up on the original request  for a test suite for CLI commands.
Also has a small fix for argument mismatch in haas/cli.py.
It's not clear to me how this should work; this looks like it's just going to try to call the `FakeResponse` object, which isn't going to do the right thing. Perhaps look at implementing the `__call__` method in `FakeResponse`?