diff --git a/tests/functional/nars.sh b/tests/functional/nars.sh
index ba5a69bd2..eaf9cd4e5 100755
--- a/tests/functional/nars.sh
+++ b/tests/functional/nars.sh
@@ -8,6 +8,9 @@ clearStore
 rm -rf "$TEST_ROOT/out"
 expectStderr 1 nix-store --restore "$TEST_ROOT/out" < duplicate.nar | grepQuiet "NAR directory is not sorted"
 
+# Check that nix-store --restore fails if the output already exists.
+expectStderr 1 nix-store --restore "$TEST_ROOT/out" < duplicate.nar | grepQuiet "path '.*/out/' already exists"
+
 # Check whether restoring and dumping a NAR that contains case
 # collisions is round-tripping, even on a case-insensitive system.
 rm -rf "$TEST_ROOT/case"