Combine CyTestMixin and TestCase; use savepoints more
Combine CyTestMixin and TestCase; use savepoints more

No speed difference was observed.

akeym/cyder,OSU-Net/cyder,zeeman/cyder,drkitty/cyder,OSU-Net/cyder,zeeman/cyder,murrown/cyder,zeeman/cyder,akeym/cyder,drkitty/cyder,zeeman/cyder,drkitty/cyder,murrown/cyder,OSU-Net/cyder,murrown/cyder,akeym/cyder,OSU-Net/cyder,murrown/cyder,drkitty/cyder,akeym/cyder