If the setup/teardown is expensive I would do it in reusable fixtures. The reason I wouldn't choose the latter approach is that it would usually be less convenient in the long run. You'd need to replace your asserts with expects to avoid it throwing on the first error (if this isn't what you want), you'll often need to manually add data to the assertion (as GP did) that you would otherwise get for free, and you'll need to look at the assertion error rather than the test case to know what actually failed. This can be quite inconvenient if you e.g. export your test results in a CI/CD pipeline.