diff --git a/mkosi.build b/mkosi.build
index 0e90480c6d..ede394f4fd 100755
--- a/mkosi.build
+++ b/mkosi.build
@@ -91,7 +91,7 @@ cd "$BUILDDIR"
 ninja
 if [ "$WITH_TESTS" = 1 ] ; then
         for id in 1 2 3; do
-                groupadd -g $id testgroup$id || :
+                getent group $id > /dev/null || groupadd -g $id testgroup$id
         done
 
         ninja test