diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index df595a7..4fa71b9 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -21,7 +21,8 @@ jobs:
       - name: 'Check out code'
         uses: actions/checkout@v4
         with:
-          token: ${{ secrets.JENKINS_GITHUB_PAT }}
+          # Check out pull request HEAD instead of merge commit.
+          ref: ${{ github.event.pull_request.head.sha }}
           submodules: recursive
 
       - name: "Set up nightly Rust" # https://github.com/rust-lang/rustup/issues/3409