A general comment - most of these test cases coule be represented by a single method with parameters (type name, value) or (typename, value, excpected exception).

My first preference would be for a test generator or data-driven test.  Failing that, the individual test methods should simply call your test generator method so we don't have so much code duplication.  If we can't do the data driven test right now, let's file a bug and schedule this for a later milestone.