From 3283d1a2f29496d882b6edc57543446967dc8233 Mon Sep 17 00:00:00 2001
From: Tamir Duberstein <tamird@google.com>
Date: Tue, 12 Oct 2021 16:00:23 -0400
Subject: [PATCH] os: Simplify size using io.Discard.

Change-Id: Ib7cc86643a3dcae788a94472e54de171e0d655fc
Reviewed-on: https://go-review.googlesource.com/c/go/+/355449
Trust: Michael Pratt <mpratt@google.com>
Trust: Keith Randall <khr@golang.org>
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Pratt <mpratt@google.com>
---
 src/os/os_test.go | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/src/os/os_test.go b/src/os/os_test.go
index 62173d9bf4..717330e86a 100644
--- a/src/os/os_test.go
+++ b/src/os/os_test.go
@@ -115,20 +115,16 @@ func size(name string, t *testing.T) int64 {
 	if err != nil {
 		t.Fatal("open failed:", err)
 	}
-	defer file.Close()
-	var buf [100]byte
-	len := 0
-	for {
-		n, e := file.Read(buf[0:])
-		len += n
-		if e == io.EOF {
-			break
-		}
-		if e != nil {
-			t.Fatal("read failed:", e)
+	defer func() {
+		if err := file.Close(); err != nil {
+			t.Error(err)
 		}
+	}()
+	n, err := io.Copy(io.Discard, file)
+	if err != nil {
+		t.Fatal(err)
 	}
-	return int64(len)
+	return n
 }
 
 func equal(name1, name2 string) (r bool) {
-- 
2.48.1