Being able to run unittest-based tests out of the box is definitely a very powerful feature, because it allows you to start using pytest right away as a runner.
Eventually, you need to decide what to do with the existing unittest-based tests. There are a few approaches you can choose:
- Convert everything: if your test suite is relatively small, you might decide to convert all tests at once. This has the advantage that you don't have to make compromises to keep existing unittest suites working, and being simpler to be reviewed by others because your pull request will have a single theme.
- Convert as you go: you might decide to convert tests and functionality as needed. When you need to add new tests or change existing tests, you take the opportunity to convert tests and/or refactor functionality to fixtures using the techniques from the previous sections...