init
Add minitest as a dev dependency

Eventually we're gong to test the testing framework in itself, _metametameta_
Runnable finds all runnable tests
Test knows how to run it's own tests
Basic assertion
Runnable#run must be implemented in each subclass
Subclasses handle their own test-running
Pass through errors that can be of use to the user
Run all tests if no test is given
so meta, wow
Fail on empty tests or tests with no assertions

This is TDD, do you speak it?
Words
Add test task for rake
Test error classes
Test refute and assert
Include modules before constant assignments
Time each testrun
Clearer error testing
Add assert_equal and refute_equal
Clearer assertion tests

Test that each assertion does what it's supposed to, and make a fuss if
the number of assertions doesn't add up