Build a wheel once, for all test environments

[kurtmckee]

The test suite currently builds a .tar.gz file, but when it's installed in each tox environment, pip converts the .tar.gz file to a wheel and then installs it.

This PR eliminates the intermediary .tar.gz file and just builds the wheel once for all environments.

---

For verification, you can run tox -vvvvve py312 before and after.

Package installation step (before)

py312: 874 W install_package> python -I -m pip install --force-reinstall --no-deps /home/kurt/dev/pr-pypa-readme_renderer/.tox/.tmp/package/45/readme_renderer-43.0.tar.gz [tox/tox_env/api.py:425]
Processing ./.tox/.tmp/package/45/readme_renderer-43.0.tar.gz
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
  Preparing metadata (pyproject.toml) ... done
Building wheels for collected packages: readme_renderer
  Building wheel for readme_renderer (pyproject.toml) ... done
  Created wheel for readme_renderer: filename=readme_renderer-43.0-py3-none-any.whl size=13304 sha256=534ec0e0a66e38098ca98b4c2043c07f33557c0483c4604e8c1ad623694416c9
  Stored in directory: /home/kurt/.cache/pip/wheels/b3/1f/e0/093a05dd510eee76ab487c953f8603b49fe1ae082ce051dd60
Successfully built readme_renderer
Installing collected packages: readme_renderer
  Attempting uninstall: readme_renderer
    Found existing installation: readme_renderer 43.0
    Uninstalling readme_renderer-43.0:
      Successfully uninstalled readme_renderer-43.0
Successfully installed readme_renderer-43.0
py312: 3266 I exit 0 (2.39 seconds) /home/kurt/dev/pr-pypa-readme_renderer> python -I -m pip install --force-reinstall --no-deps /home/kurt/dev/pr-pypa-readme_renderer/.tox/.tmp/package/45/readme_renderer-43.0.tar.gz pid=103997 [tox/execute/api.py:286]

:point_up: 2.39 seconds to convert the .tar.gz file to a .whl and install it

Package installation step (after)

py312: 861 W install_package> python -I -m pip install --force-reinstall --no-deps /home/kurt/dev/pr-pypa-readme_renderer/.tox/.tmp/package/46/readme_renderer-43.0-py3-none-any.whl [tox/tox_env/api.py:425]
Processing ./.tox/.tmp/package/46/readme_renderer-43.0-py3-none-any.whl
Installing collected packages: readme-renderer
  Attempting uninstall: readme-renderer
    Found existing installation: readme_renderer 43.0
    Uninstalling readme_renderer-43.0:
      Successfully uninstalled readme_renderer-43.0
Successfully installed readme-renderer-43.0
py312: 1309 I exit 0 (0.45 seconds) /home/kurt/dev/pr-pypa-readme_renderer> python -I -m pip install --force-reinstall --no-deps /home/kurt/dev/pr-pypa-readme_renderer/.tox/.tmp/package/46/readme_renderer-43.0-py3-none-any.whl pid=104486 [tox/execute/api.py:286]

:point_up: 0.45 seconds to install the .whl file

[kurtmckee]

[!NOTE]

CI is failing, but it is unrelated to this change. The test suite fails locally prior to this change, too.

[kurtmckee]

Rebased on main

[kurtmckee]

Friendly reminder to take a peek at this. :grinning:

When running tox locally, this reduces the total test time by ~40% (from ~44 seconds to ~26 seconds):

BEFORE

  py39: OK (3.41=setup[2.66]+cmd[0.75] seconds)
  py310: OK (2.83=setup[2.04]+cmd[0.79] seconds)
  py311: OK (2.79=setup[2.04]+cmd[0.75] seconds)
  py312: OK (3.68=setup[2.17]+cmd[1.51] seconds)
  pypy39: OK (7.71=setup[3.62]+cmd[4.09] seconds)
  pypy310: OK (7.72=setup[3.65]+cmd[4.07] seconds)
  pep8: OK (0.13=setup[0.00]+cmd[0.12] seconds)
  packaging: OK (9.58=setup[2.34]+cmd[3.59,3.40,0.25] seconds)
  noextra: OK (3.60=setup[2.20]+cmd[1.40] seconds)
  mypy: OK (2.29=setup[2.18]+cmd[0.11] seconds)
  congratulations :) (43.87 seconds)

AFTER

  py39: OK (1.77=setup[1.03]+cmd[0.74] seconds)
  py310: OK (1.21=setup[0.40]+cmd[0.80] seconds)
  py311: OK (1.16=setup[0.40]+cmd[0.76] seconds)
  py312: OK (1.91=setup[0.43]+cmd[1.48] seconds)
  pypy39: OK (4.71=setup[0.72]+cmd[3.99] seconds)
  pypy310: OK (4.59=setup[0.73]+cmd[3.86] seconds)
  pep8: OK (0.12=setup[0.00]+cmd[0.12] seconds)
  packaging: OK (7.58=setup[0.44]+cmd[3.56,3.33,0.25] seconds)
  noextra: OK (1.78=setup[0.43]+cmd[1.35] seconds)
  mypy: OK (0.54=setup[0.43]+cmd[0.11] seconds)
  congratulations :) (25.49 seconds)