diff --git a/.github/workflows/test_suite.yml b/.github/workflows/test_suite.yml
index e484eea..d4a38a4 100644
--- a/.github/workflows/test_suite.yml
+++ b/.github/workflows/test_suite.yml
@@ -28,3 +28,4 @@ jobs:
         **/*.py
         **/*.msh
         **/*.geo
+      docker-image: firedrake-um2n