Change tox behavior

[pepoluan]

What do these changes do?

I had just managed to b0rk my cloned repo completely when I specify tox to run pypy38-nocov.

That is due to envdir not specified explicitly so tox decides to 'clean up' my cloned repo and build its environment right there.

After recloning, I found out that tox now will recreate environment if the envname changes, so py37-nocov and py37-cov (for instance) can no longer share same packages. Meaning that previous "common deps" list is useless.

So I decided to just specify a specific envdir for all envname (i.e., combination of Pyton version + what test), and use conditionals on the deps installation.

Are there changes in behavior for the user?

Not really. However developers might find that hard disk usage balloons. Use housekeep.py superclean, it's there for a reason 😉

Related issue number

None

Checklist

• [x] I think the code is well written
• [x] tox testenvs have been executed in the following environments:
  • [x] Windows (10): pypy38-{nocov,cov}

[pepoluan]

I'm squamerging this rather urgently because I don't want the calamity that befell me happen to others.