From 9bd34ebb7e820922458929c9a1146fb0a5b0ca4d Mon Sep 17 00:00:00 2001
From: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Date: Sat, 14 Sep 2024 06:37:33 +0700
Subject: [PATCH] unicode/utf8: add test that RuneCount does zero allocations

See disccusion in CL 612955.

Change-Id: I2de582321648f1798929ffb80d2f087e41146ead
Reviewed-on: https://go-review.googlesource.com/c/go/+/613315
Commit-Queue: Ian Lance Taylor <iant@google.com>
Reviewed-by: Tim King <taking@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>
---
 src/unicode/utf8/utf8_test.go | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/unicode/utf8/utf8_test.go b/src/unicode/utf8/utf8_test.go
index 2adec97541..69362d2cf1 100644
--- a/src/unicode/utf8/utf8_test.go
+++ b/src/unicode/utf8/utf8_test.go
@@ -438,6 +438,15 @@ func TestRuneCount(t *testing.T) {
 	}
 }
 
+func TestRuneCountNonASCIIAllocation(t *testing.T) {
+	if n := testing.AllocsPerRun(10, func() {
+		s := []byte("日本語日本語日本語日")
+		_ = RuneCount(s)
+	}); n > 0 {
+		t.Errorf("unexpected RuneCount allocation, got %v, want 0", n)
+	}
+}
+
 type RuneLenTest struct {
 	r    rune
 	size int
-- 
2.48.1