diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index ae2d7ed..bdf3b60 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -21,6 +21,7 @@ jobs:
           node-version: ${{ steps.nvm.outputs.NVMRC }}
       - run: npm ci
       - run: npm run all
+      - run: git diff --quiet
   test: # make sure the action works on a clean machine without building
     runs-on: ubuntu-latest
     steps: