Use pytest

[ml31415]

I understand your frustration with stdlib unittest. Though, instead of reinventing just another test suite, not that well tested and supported, just for testing ponyorm, pls just consider using pytest instead. There is just no value in having a kind of private separate test suite, if you just could use a perfectly battle tested workhorse like pytest. Please don't fall with the not-invented-here-phenomenon! And all other really pony specific stuff should just be part of the test cases there...