diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index f741e553..a4674093 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -10,6 +10,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
+      with:
+        ref: ${{ github.event.pull_request.head.sha }}
     - uses: actions/setup-node@v1
       with:
         node-version: 10.x