TODO
- Use datatypes instead of strings and tuples (see smell-spec)
- Display time to run tests (again, see smell-spec)
- Add a When construct to enable better specification of context for specs (yet again, see smell-spec)
- Add matchers for more types and formatters for output (see sml-testing)
- Add watch capability (see stupid)
- Change so that progress dots are printed sequentially instead of printing everything at once
- Change so that "it" is given the value of the last failing spec, so the repl can represent polymorphic values used in a comparison e.g. for toBe