ci: license/README/packaging light job, pytest on the PR head (#243 follow-up)

.github/workflows/test.yml

@@ -247,6 +247,39 @@ jobs:
           fi
           "$lint_dir/actionlint" -config-file "$lint_dir/actionlint.yaml" -shellcheck= -pyflakes= "${workflows[@]}"
 
+  package-files:
+    name: package-files
+    needs: [authz]
+    runs-on: ubuntu-24.04
+    permissions:
+      contents: read
+    steps:
+      - name: "Check out the exact head"
+        if: "${{ needs.authz.result == 'success' }}"
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          ref: "${{ github.event.pull_request.head.sha || github.sha }}"
+          fetch-depth: 0
+          persist-credentials: false
+      - name: "Require package metadata files"
+        if: "${{ needs.authz.result == 'success' }}"
+        shell: "bash"
+        run: |
+          set -eu
+          test -f LICENSE
+          test -f README.md
+      - name: "Set up Python"
+        if: "${{ needs.authz.result == 'success' }}"
+        uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v7.0.0
+        with:
+          python-version: "3.11"
+      - name: "Install test dependencies"
+        if: "${{ needs.authz.result == 'success' }}"
+        run: python -m pip install -e ".[dev]"
+      - name: "Run license and entity check"
+        if: "${{ needs.authz.result == 'success' }}"
+        run: python -m pytest -q tests/test_license_entity.py
+
   pytest:
     needs: [authz, changes]
     if: needs.changes.outputs.code == 'true'
@@ -261,7 +294,7 @@ jobs:
     steps:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
-          ref: ${{ github.sha }}
+          ref: "${{ github.event.pull_request.head.sha || github.sha }}"
           fetch-depth: 0
           persist-credentials: false
       - uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v7.0.0
@@ -273,7 +306,7 @@ jobs:
         run: python -m pytest -q
 
   test-check:
-    needs: [authz, changes, workflow-lint, pytest]
+    needs: [authz, changes, workflow-lint, package-files, pytest]
     if: ${{ always() }}
     runs-on: ubuntu-24.04
     permissions: