migrate test framework from nose to pytest

[monkut]

Context

As per the nose documentation:

Nose has been in maintenance mode for the past several years and will likely cease without a new person/team to take over maintainership. New projects should consider using Nose2, py.test, or just plain unittest/unittest2.

As nose is no longer under development the test framework should be updated to a framework which is more active.

Expected Behavior

Testcases run under the new framework

Actual Behavior

nose is still used

Possible Fix

Migrate the test framework to pytest.

[monkut]

Supported in 0.57.0 release, published to pypi 5/19, closing.