test-unit-must is a set of assertions for Test::Unit that treat
the receiver of an assertion method call as the subject of the
assertion. In other words, these are MiniTest::Spec style
assertions, but their names only begin with `must_` or `must_not_`;
there is no `wont_` or `refute_` prefix.
What is new?
* Support more Test::Unit 2 assertions to be 100% feature complete: