action: upload artifact being signed for

.github/workflows/selftest.yml

@@ -95,6 +95,17 @@ jobs:
           inputs: ./test/artifact.txt
           staging: true
           upload-signing-artifacts: true
+      - uses: actions/download-artifact@v3
+        with:
+          name: "signing-artifacts-${{ github.job }}"
+          path: ./test/uploaded
+      - name: Verify presence of uploaded files
+        run: |
+          [[ -f ./artifact.txt ]] || exit 1
+          [[ -f ./artifact.txt.sig ]] || exit 1
+          [[ -f ./artifact.txt.crt ]] || exit 1
+          [[ -f ./artifact.txt.sigstore ]] || exit 1
+        working-directory: ./test/uploaded
 
   selftest-custom-paths:
     runs-on: ubuntu-latest

action.py

@@ -200,6 +200,10 @@ def _fatal_help(msg):
     for file_ in files:
         if not file_.is_file():
             _fatal_help(f"input {file_} does not look like a file")
+
+        # Also upload artifact being signed for.
+        signing_artifact_paths.append(file_)
+
         if not bundle_only and "--certificate" not in sigstore_sign_args:
             signing_artifact_paths.append(f"{file_}.crt")
         if not bundle_only and "--signature" not in sigstore_sign_args: