diff --git a/.github/workflows/pr.yaml b/.github/workflows/pr.yaml
index f89ccf3..ce1fc63 100644
--- a/.github/workflows/pr.yaml
+++ b/.github/workflows/pr.yaml
@@ -13,6 +13,10 @@ jobs:
     steps:
     - name: Clone
       uses: actions/checkout@v2
+    - name: Build
+      uses: docker://alpine:latest
+      with:
+        args: ls
     - name: Build
       uses: docker://nixos/nix
       with: