In pytest tests, implement start and end fixtures
Some tests change the pretending mode of Debug object which is singleton.
In perl tests are behaving so that one test does not influence on another. In pytest, it is different.
Currently, I have added a deletion of Debug object after tests that change pretending.
Would be nice to create a fixture applied to them, so it is done automatically.
In unittest the corresponding methods are setUp and tearDown. Need to make similar thing with pytest.