Because setup.py uses find_packages and tests is on the top-level, pip install datasette will install a top-level package called tests, which is probably not desired behavior.

The offending line is here:

And only pip uninstall datasette with a conflicting package would warn you by default; apparently another package had the same problem, which is why I get this message when uninstalling:

$ pip uninstall datasette
Uninstalling datasette-0.27:
  Would remove:
    /usr/local/bin/datasette
    /usr/local/lib/python3.7/site-packages/datasette-0.27.dist-info/*
    /usr/local/lib/python3.7/site-packages/datasette/*
    /usr/local/lib/python3.7/site-packages/tests/*
  Would not remove (might be manually added):
    [ .. snip .. ]
Proceed (y/n)? 

This should be a relatively simple fix, and I could drop a PR if desired!

Cheers