workflows: Re-run tests in an unpacked sdist

This is analogous to Autotools make distcheck or Meson ninja dist. It
verifies that the sdist works correctly, and contains everything necessary
to build, test and install.

Signed-off-by: Simon McVittie <smcv@debian.org>

Author: smcv

.github/workflows/main.yml

@@ -37,3 +37,11 @@ jobs:
       - name: Run tests
         run: |
           python -m pytest
+      - name: Test source distribution
+        run: |
+          rm -fr dist
+          python setup.py sdist
+          tar -C dist -axvf dist/*.tar.gz
+          ( cd dist/*/; python setup.py build )
+          ( cd dist/*/; python -m pytest )
+          ( cd dist/*/; python setup.py install --user )