diff --git a/tests/optimise-store.sh b/tests/optimise-store.sh
index 4d8077997..6eb54ca50 100644
--- a/tests/optimise-store.sh
+++ b/tests/optimise-store.sh
@@ -2,8 +2,8 @@ source common.sh
 
 clearStore
 
-outPath1=$(echo 'with import ./config.nix; mkDerivation { name = "foo1"; builder = builtins.toFile "builder" "mkdir $out; echo hello > $out/foo"; }' | nix-build - --no-out-link)
-outPath2=$(echo 'with import ./config.nix; mkDerivation { name = "foo2"; builder = builtins.toFile "builder" "mkdir $out; echo hello > $out/foo"; }' | nix-build - --no-out-link)
+outPath1=$(echo 'with import ./config.nix; mkDerivation { name = "foo1"; builder = builtins.toFile "builder" "mkdir $out; echo hello > $out/foo"; }' | nix-build - --no-out-link --option auto-optimise-store true)
+outPath2=$(echo 'with import ./config.nix; mkDerivation { name = "foo2"; builder = builtins.toFile "builder" "mkdir $out; echo hello > $out/foo"; }' | nix-build - --no-out-link --option auto-optimise-store true)
 
 inode1="$(perl -e "print ((lstat('$outPath1/foo'))[1])")"
 inode2="$(perl -e "print ((lstat('$outPath2/foo'))[1])")"