Add allow function.
Move setup/teardown/verify to lifecycle module.
Add expect function.
Use native stack traces for Pytest failures.
Use a function to access the current space.
Move lifecycle setup/teardown to conftest.py so it affects all tests.
Remove tests. Gonna start over much higher level.
Implement repr for doubles.
Manually run coverage since pytest-cov doesn't start early enough.
Implement basic method double.
Raise an exception if an unallowed method is called on a double.
Add failing test case for message expectations.