test_starters.py is very slow

[deepyaman]

I'm running the full test suite now, and, anecdotally, it seems like an exorbitant amount of time is spent on test_starters.py. Looking into the test suite, there are parametrizations for every spelling and characterization.

I feel like the time could be reduced significantly by patching and checking inputs being sent downstream, rather than actually going through project creation and deletion for every combination?

[merelcht]

I created a ticket for refactoring test_starters.py: #3594, maybe we can merge them?