workflows: Re-run tests in an unpacked sdist

This 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 )