diff --git a/t/t4200-rerere.sh b/t/t4200-rerere.sh
index 8f5f268baf..1e23031cdb 100755
--- a/t/t4200-rerere.sh
+++ b/t/t4200-rerere.sh
@@ -420,19 +420,28 @@ count_pre_post () {
 }
 
 test_expect_success 'rerere gc' '
-	find .git/rr-cache -type f >original &&
-	xargs test-chmtime -172800 <original &&
+	rm -fr .git/rr-cache &&
+	rr=.git/rr-cache/$_z40 &&
+	mkdir -p "$rr" &&
+	>"$rr/preimage" &&
+	>"$rr/postimage" &&
+
+	two_days_ago=$((-2*86400)) &&
+	test-chmtime =$two_days_ago "$rr/preimage" &&
+	test-chmtime =$two_days_ago "$rr/postimage" &&
+
+	find .git/rr-cache -type f | sort >original &&
 
 	git -c gc.rerereresolved=5 -c gc.rerereunresolved=5 rerere gc &&
-	find .git/rr-cache -type f >actual &&
+	find .git/rr-cache -type f | sort >actual &&
 	test_cmp original actual &&
 
 	git -c gc.rerereresolved=5 -c gc.rerereunresolved=0 rerere gc &&
-	find .git/rr-cache -type f >actual &&
+	find .git/rr-cache -type f | sort >actual &&
 	test_cmp original actual &&
 
 	git -c gc.rerereresolved=0 -c gc.rerereunresolved=0 rerere gc &&
-	find .git/rr-cache -type f >actual &&
+	find .git/rr-cache -type f | sort >actual &&
 	>expect &&
 	test_cmp expect actual
 '