Add test for postinstall (#2392)

Author: Avasam

.github/workflows/main.yml

@@ -45,10 +45,18 @@ jobs:
       # This needs to happen *after* installing pywin32 since
       # AutoDuck/py2d.py currently relies on runtime imports for introspection
       # This isn't included in the wheel (TODO: could we?)
-      # and only servces as a PR test for the docs.yaml workflow
+      # and only serves as a PR test for the docs.yaml workflow
       - name: Generate PyWin32.chm help file
         run: python AutoDuck/make.py
 
+      # Smokescreen test to validate it doesn't crash and dlls can be found
+      - name: Run postinstall install/remove
+        run: |
+          $UserSite = "$(python -m site --user-site)"
+          cd "$UserSite/.."
+          python Scripts/pywin32_postinstall.py -install -destination "$UserSite"
+          python Scripts/pywin32_postinstall.py -remove -destination "$UserSite"
+
       - name: Run tests
         # Run the tests directly from the source dir so support files (eg, .wav files etc)
         # can be found - they aren't installed into the Python tree.