From 1d905e0b1cbbeb37378c0380b58a6f5194fc401a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=ABl=20Stemmer?= <stemmertech@gmail.com>
Date: Sun, 12 Jun 2022 22:56:04 +0100
Subject: [PATCH] gtr: Improve accuracy of benchmark duration calculation

The NsPerOp was previously casted to a time.Duration (int64) before
multiplying it with the number of iterations. This has been fixed by
doing the casting after the multiplication. The resulting duration
should be a bit more accurate.
---
 gtr/gtr.go              | 2 +-
 testdata/022-report.xml | 4 ++--
 testdata/024-report.xml | 4 ++--
 testdata/025-report.xml | 4 ++--
 testdata/027-report.xml | 6 +++---
 testdata/028-report.xml | 2 +-
 testdata/109-report.xml | 4 ++--
 7 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/gtr/gtr.go b/gtr/gtr.go
index 5fb23fa..f8f3009 100644
--- a/gtr/gtr.go
+++ b/gtr/gtr.go
@@ -106,7 +106,7 @@ type Benchmark struct {
 // ApproximateDuration returns the duration calculated by multiplying the
 // iterations and average time per iteration (NsPerOp).
 func (b Benchmark) ApproximateDuration() time.Duration {
-	return time.Duration(b.NsPerOp) * time.Duration(b.Iterations)
+	return time.Duration(float64(b.Iterations)*b.NsPerOp) * time.Nanosecond
 }
 
 // Error contains details of a build or runtime error.
diff --git a/testdata/022-report.xml b/testdata/022-report.xml
index d5d3699..bf3282a 100644
--- a/testdata/022-report.xml
+++ b/testdata/022-report.xml
@@ -7,7 +7,7 @@
 		<testcase name="TestOne" classname="package/bench" time="0.000">
 			<system-out><![CDATA[    bench_test.go:9: test log]]></system-out>
 		</testcase>
-		<testcase name="BenchmarkOne" classname="package/bench" time="0.000000000">
+		<testcase name="BenchmarkOne" classname="package/bench" time="0.264200000">
 			<system-out><![CDATA[    bench_test.go:13: benchmark log (1)
     bench_test.go:13: benchmark log (100)
     bench_test.go:13: benchmark log (10000)
@@ -15,7 +15,7 @@
     bench_test.go:13: benchmark log (100000000)
     bench_test.go:13: benchmark log (1000000000)]]></system-out>
 		</testcase>
-		<testcase name="BenchmarkTwo" classname="package/bench" time="1.305496599"></testcase>
+		<testcase name="BenchmarkTwo" classname="package/bench" time="1.313804304"></testcase>
 		<system-out><![CDATA[goos: linux
 goarch: amd64
 pkg: package/bench]]></system-out>
diff --git a/testdata/024-report.xml b/testdata/024-report.xml
index 636391e..922edd0 100644
--- a/testdata/024-report.xml
+++ b/testdata/024-report.xml
@@ -4,8 +4,8 @@
 		<properties>
 			<property name="go.version" value="1.0"></property>
 		</properties>
-		<testcase name="BenchmarkOne" classname="package/bench" time="0.000000000"></testcase>
-		<testcase name="BenchmarkTwo" classname="package/bench" time="1.312990536"></testcase>
+		<testcase name="BenchmarkOne" classname="package/bench" time="0.264000000"></testcase>
+		<testcase name="BenchmarkTwo" classname="package/bench" time="1.316969295"></testcase>
 		<system-out><![CDATA[goos: linux
 goarch: amd64
 pkg: package/bench
diff --git a/testdata/025-report.xml b/testdata/025-report.xml
index b430ad7..859d6f9 100644
--- a/testdata/025-report.xml
+++ b/testdata/025-report.xml
@@ -4,7 +4,7 @@
 		<properties>
 			<property name="go.version" value="1.0"></property>
 		</properties>
-		<testcase name="BenchmarkNew" classname="pkg/count" time="8.800000000"></testcase>
-		<testcase name="BenchmarkFew" classname="pkg/count" time="2.550000000"></testcase>
+		<testcase name="BenchmarkNew" classname="pkg/count" time="8.820000000"></testcase>
+		<testcase name="BenchmarkFew" classname="pkg/count" time="2.555000000"></testcase>
 	</testsuite>
 </testsuites>
diff --git a/testdata/027-report.xml b/testdata/027-report.xml
index 7a535bc..da9d39c 100644
--- a/testdata/027-report.xml
+++ b/testdata/027-report.xml
@@ -4,9 +4,9 @@
 		<properties>
 			<property name="go.version" value="1.0"></property>
 		</properties>
-		<testcase name="BenchmarkItsy" classname="really/small" time="1.350000000"></testcase>
-		<testcase name="BenchmarkTeeny" classname="really/small" time="2.000000000"></testcase>
-		<testcase name="BenchmarkWeeny" classname="really/small" time="0.000000000"></testcase>
+		<testcase name="BenchmarkItsy" classname="really/small" time="1.371000000"></testcase>
+		<testcase name="BenchmarkTeeny" classname="really/small" time="2.120000000"></testcase>
+		<testcase name="BenchmarkWeeny" classname="really/small" time="0.520000000"></testcase>
 		<system-out><![CDATA[goos: darwin
 goarch: amd64
 pkg: really/small]]></system-out>
diff --git a/testdata/028-report.xml b/testdata/028-report.xml
index da67e7f..afb4dd9 100644
--- a/testdata/028-report.xml
+++ b/testdata/028-report.xml
@@ -4,7 +4,7 @@
 		<properties>
 			<property name="go.version" value="1.0"></property>
 		</properties>
-		<testcase name="BenchmarkRing" classname="single/cpu" time="1.480000000"></testcase>
+		<testcase name="BenchmarkRing" classname="single/cpu" time="1.484000000"></testcase>
 		<system-out><![CDATA[pkg: single/cpu]]></system-out>
 	</testsuite>
 </testsuites>
diff --git a/testdata/109-report.xml b/testdata/109-report.xml
index 378bd54..2fb4728 100644
--- a/testdata/109-report.xml
+++ b/testdata/109-report.xml
@@ -10,7 +10,7 @@
 		<testcase name="TestZ" classname="package/name/bench" time="0.000">
 			<system-out><![CDATA[    z_test.go:6: ok]]></system-out>
 		</testcase>
-		<testcase name="BenchmarkTest" classname="package/name/bench" time="0.000000000">
+		<testcase name="BenchmarkTest" classname="package/name/bench" time="0.440700000">
 			<system-out><![CDATA[    bench_test.go:12: 1
     bench_test.go:12: 100
     bench_test.go:12: 10000
@@ -18,7 +18,7 @@
     bench_test.go:12: 100000000
     bench_test.go:12: 1000000000]]></system-out>
 		</testcase>
-		<testcase name="BenchmarkOtherTest" classname="package/name/bench" time="0.000000000"></testcase>
+		<testcase name="BenchmarkOtherTest" classname="package/name/bench" time="0.263900000"></testcase>
 		<system-out><![CDATA[goos: linux
 goarch: amd64
 pkg: package/name/bench]]></system-out>