diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
index 561796f..069e4e2 100755
--- a/t/t5318-commit-graph.sh
+++ b/t/t5318-commit-graph.sh
@@ -75,7 +75,7 @@
 
 test_expect_success 'write graph' '
 	cd "$TRASH_DIRECTORY/full" &&
-	graph1=$(git commit-graph write) &&
+	git commit-graph write &&
 	test_path_is_file $objdir/info/commit-graph &&
 	graph_read_expect "3"
 '