It’s not necessarily accidental, but more about researching as to how to run the tests. So things like RPM I believe let you specify how to run the test suite, so whomever repackages the Python project has to look that up.
I view it as a 3-step process:
Get the test code included in the sdists (the whole point of this topic; the “where”)
Be able to specify what the tests must have installed (which came up in this discussion as getting people to specify a test extra)
Be able to specify how to run the tests (this has not been discussed and is a separate topic)
I’m not sure if people view steps 1-2 not useful w/o 3, or if step 3 is a separate thing but isn’t useful w/o steps 1-2.