diff --git a/backend/headless/output.c b/backend/headless/output.c
index 1f81f0b9..15283136 100644
--- a/backend/headless/output.c
+++ b/backend/headless/output.c
@@ -98,6 +98,7 @@ static void output_destroy(struct wlr_output *wlr_output) {
 
 static const struct wlr_output_impl output_impl = {
 	.destroy = output_destroy,
+	.test = output_test,
 	.commit = output_commit,
 	.set_cursor = output_set_cursor,
 	.move_cursor = output_move_cursor,