This strengthens the argument I’m making, no? You bring in the source repo when doing development and debugging. In either case - tarball or not - it doesn’t seem that difficult to nuke the test dir before building a release for distribution. Again, only really necessary if you have opaque blobs where fishy things can hide.
The distributions often run the same tests after it’s built to make sure it’s working correctly as built in the distribution environment. This can and does find real problems.
