Uncomment commented-out test.
Refactor tests into usage, unit and integration.

Usage tests should demonstrate the usage of a feature, and act as
integration tests (invariant over different implementations).

Integration tests should drive kintama from a high level to exercise
features such as command-line options.

Unit tests should demonstrate the internal behaviour of various objects
like `Test` or `Context` instances.
Try and make the tests even more descriptive and clearer demonstrations of usage.
More test clarity work.

I want the usage tests to be as readable as Cucumber features.
Ordering them is one way to encourage them as this kind of executable
specification of what Kintama can do.