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.
Python provides a special syntax for class/function/module level documentation (docstrings):

    class FakeResponse:
        """Mock object for testing HTTP requests"""

You should use these instead of block comments near the class/function/top of module -- among other things, tools like `pydoc` will pick these up.