Save file on test failure

Fixes #1366

.github/workflows/tests.yml

@@ -19,4 +19,11 @@ jobs:
       - name: Copy configuration
         run: cp config.json.example config.json
       - name: Run tests
-        run: npm run test
+        run: npm run test
+
+      - name: Upload results on fail
+        if: ${{ failure() }}
+        uses: actions/upload-artifact@v3
+        with:
+          name: Test Results
+          path: ./test-results