From 79fab70a63e03897db384fbf1b5fdeeb6f9f4b92 Mon Sep 17 00:00:00 2001
From: Marcel van Lohuizen <mpvl@golang.org>
Date: Tue, 14 Feb 2017 13:01:18 +0100
Subject: [PATCH] testing: fix stats bug for sub benchmarks

Fixes golang/go#18815.

Change-Id: Ic9d5cb640a555c58baedd597ed4ca5dd9f275c97
Reviewed-on: https://go-review.googlesource.com/36990
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
---
 src/testing/benchmark.go |  3 ---
 src/testing/sub_test.go  | 20 ++++++++++++++++++++
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/src/testing/benchmark.go b/src/testing/benchmark.go
index 3233347dcbd..86c0f10ecdc 100644
--- a/src/testing/benchmark.go
+++ b/src/testing/benchmark.go
@@ -657,9 +657,6 @@ func Benchmark(f func(b *B)) BenchmarkResult {
 		benchFunc: f,
 		benchTime: *benchTime,
 	}
-	if !b.run1() {
-		return BenchmarkResult{}
-	}
 	return b.run()
 }
 
diff --git a/src/testing/sub_test.go b/src/testing/sub_test.go
index c12a2c807ab..fe3e8ff8581 100644
--- a/src/testing/sub_test.go
+++ b/src/testing/sub_test.go
@@ -15,6 +15,11 @@ import (
 	"time"
 )
 
+func init() {
+	// Make benchmark tests run 10* faster.
+	*benchTime = 100 * time.Millisecond
+}
+
 func TestTestContext(t *T) {
 	const (
 		add1 = 0
@@ -581,3 +586,18 @@ func TestRacyOutput(t *T) {
 		t.Errorf("detected %d racy Writes", races)
 	}
 }
+
+func TestBenchmark(t *T) {
+	res := Benchmark(func(b *B) {
+		for i := 0; i < 5; i++ {
+			b.Run("", func(b *B) {
+				for i := 0; i < b.N; i++ {
+					time.Sleep(time.Millisecond)
+				}
+			})
+		}
+	})
+	if res.NsPerOp() < 4000000 {
+		t.Errorf("want >5ms; got %v", time.Duration(res.NsPerOp()))
+	}
+}