Some time ago I wrote a pytest plugin[1] that helps me test my long running shell scripts.
The idea was to treat the shell process as a fixture, and conditions before and after the test (input file checksums, output files, generated stdout/stderr, etc.) would be checked. It was mostly for data analysis pipelines (hence the name).
I don't use it as much these days as my days of writing long running pipelines are behind me. But for that time, it did its job pretty ok. It was also a nice way to peek into pytest's internals.