Add example for __test__ (#7733)
Add example for __test__ (#7733)

Co-authored-by: Bruno Oliveira <024fc659bb4ab842ec49c8a162b11a29104488bd@gmail.com>
pytest-dev/pytest,markshao/pytest,Akasurde/pytest,nicoddemus/pytest,nicoddemus/pytest,RonnyPfannschmidt/pytest