example pytest session fixture reordering the tests

conftest.py

from pytest import fixture, Class


@fixture(scope="session", autouse=True)
def sort_tests_by_class_name(request):
    session = request.node
    key = lambda item: item.getparent(Class).obj.__name__
    session.items[:] = sorted(session.items, key=key)

the ordering is done by class name here, but __name__ could simply be replaced by layer. also see http://pytest.org/latest/example/special.html for more information.

the above file needs to be put into conftest.py in your tests directory. the altered ordering can be seen when running py.test -v...