diff --git a/t/t5539-fetch-http-shallow.sh b/t/t5539-fetch-http-shallow.sh
index 94553e1039..b46118846c 100755
--- a/t/t5539-fetch-http-shallow.sh
+++ b/t/t5539-fetch-http-shallow.sh
@@ -54,6 +54,7 @@ EOF
 test_expect_success 'no shallow lines after receiving ACK ready' '
 	(
 		cd shallow &&
+		test_tick &&
 		for i in $(test_seq 15)
 		do
 			git checkout --orphan unrelated$i &&