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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package testing_test
import (
"bytes"
"runtime"
"sort"
"strings"
"sync/atomic"
"testing"
"text/template"
"time"
)
var prettyPrintTests = []struct {
v float64
expected string
}{
{0, " 0 x"},
{1234.1, " 1234 x"},
{-1234.1, " -1234 x"},
{999.950001, " 1000 x"},
{999.949999, " 999.9 x"},
{99.9950001, " 100.0 x"},
{99.9949999, " 99.99 x"},
{-99.9949999, " -99.99 x"},
{0.000999950001, " 0.001000 x"},
{0.000999949999, " 0.0009999 x"}, // smallest case
{0.0000999949999, " 0.0001000 x"},
}
func TestPrettyPrint(t *testing.T) {
for _, tt := range prettyPrintTests {
buf := new(strings.Builder)
testing.PrettyPrint(buf, tt.v, "x")
if tt.expected != buf.String() {
t.Errorf("prettyPrint(%v): expected %q, actual %q", tt.v, tt.expected, buf.String())
}
}
}
func TestResultString(t *testing.T) {
// Test fractional ns/op handling
r := testing.BenchmarkResult{
N: 100,
T: 240 * time.Nanosecond,
}
if r.NsPerOp() != 2 {
t.Errorf("NsPerOp: expected 2, actual %v", r.NsPerOp())
}
if want, got := " 100\t 2.400 ns/op", r.String(); want != got {
t.Errorf("String: expected %q, actual %q", want, got)
}
// Test sub-1 ns/op (issue #31005)
r.T = 40 * time.Nanosecond
if want, got := " 100\t 0.4000 ns/op", r.String(); want != got {
t.Errorf("String: expected %q, actual %q", want, got)
}
// Test 0 ns/op
r.T = 0
if want, got := " 100", r.String(); want != got {
t.Errorf("String: expected %q, actual %q", want, got)
}
}
func TestRunParallel(t *testing.T) {
if testing.Short() {
t.Skip("skipping in short mode")
}
testing.Benchmark(func(b *testing.B) {
procs := uint32(0)
iters := uint64(0)
b.SetParallelism(3)
b.RunParallel(func(pb *testing.PB) {
atomic.AddUint32(&procs, 1)
for pb.Next() {
atomic.AddUint64(&iters, 1)
}
})
if want := uint32(3 * runtime.GOMAXPROCS(0)); procs != want {
t.Errorf("got %v procs, want %v", procs, want)
}
if iters != uint64(b.N) {
t.Errorf("got %v iters, want %v", iters, b.N)
}
})
}
func TestRunParallelFail(t *testing.T) {
testing.Benchmark(func(b *testing.B) {
b.RunParallel(func(pb *testing.PB) {
// The function must be able to log/abort
// w/o crashing/deadlocking the whole benchmark.
b.Log("log")
b.Error("error")
})
})
}
func TestRunParallelFatal(t *testing.T) {
testing.Benchmark(func(b *testing.B) {
b.RunParallel(func(pb *testing.PB) {
for pb.Next() {
if b.N > 1 {
b.Fatal("error")
}
}
})
})
}
func TestRunParallelSkipNow(t *testing.T) {
testing.Benchmark(func(b *testing.B) {
b.RunParallel(func(pb *testing.PB) {
for pb.Next() {
if b.N > 1 {
b.SkipNow()
}
}
})
})
}
func ExampleB_RunParallel() {
// Parallel benchmark for text/template.Template.Execute on a single object.
testing.Benchmark(func(b *testing.B) {
templ := template.Must(template.New("test").Parse("Hello, {{.}}!"))
// RunParallel will create GOMAXPROCS goroutines
// and distribute work among them.
b.RunParallel(func(pb *testing.PB) {
// Each goroutine has its own bytes.Buffer.
var buf bytes.Buffer
for pb.Next() {
// The loop body is executed b.N times total across all goroutines.
buf.Reset()
templ.Execute(&buf, "World")
}
})
})
}
func TestReportMetric(t *testing.T) {
res := testing.Benchmark(func(b *testing.B) {
b.ReportMetric(12345, "ns/op")
b.ReportMetric(0.2, "frobs/op")
})
// Test built-in overriding.
if res.NsPerOp() != 12345 {
t.Errorf("NsPerOp: expected %v, actual %v", 12345, res.NsPerOp())
}
// Test stringing.
res.N = 1 // Make the output stable
want := " 1\t 12345 ns/op\t 0.2000 frobs/op"
if want != res.String() {
t.Errorf("expected %q, actual %q", want, res.String())
}
}
func ExampleB_ReportMetric() {
// This reports a custom benchmark metric relevant to a
// specific algorithm (in this case, sorting).
testing.Benchmark(func(b *testing.B) {
var compares int64
for i := 0; i < b.N; i++ {
s := []int{5, 4, 3, 2, 1}
sort.Slice(s, func(i, j int) bool {
compares++
return s[i] < s[j]
})
}
// This metric is per-operation, so divide by b.N and
// report it as a "/op" unit.
b.ReportMetric(float64(compares)/float64(b.N), "compares/op")
// This metric is per-time, so divide by b.Elapsed and
// report it as a "/ns" unit.
b.ReportMetric(float64(compares)/float64(b.Elapsed().Nanoseconds()), "compares/ns")
})
}
func ExampleB_ReportMetric_parallel() {
// This reports a custom benchmark metric relevant to a
// specific algorithm (in this case, sorting) in parallel.
testing.Benchmark(func(b *testing.B) {
var compares atomic.Int64
b.RunParallel(func(pb *testing.PB) {
for pb.Next() {
s := []int{5, 4, 3, 2, 1}
sort.Slice(s, func(i, j int) bool {
// Because RunParallel runs the function many
// times in parallel, we must increment the
// counter atomically to avoid racing writes.
compares.Add(1)
return s[i] < s[j]
})
}
})
// NOTE: Report each metric once, after all of the parallel
// calls have completed.
// This metric is per-operation, so divide by b.N and
// report it as a "/op" unit.
b.ReportMetric(float64(compares.Load())/float64(b.N), "compares/op")
// This metric is per-time, so divide by b.Elapsed and
// report it as a "/ns" unit.
b.ReportMetric(float64(compares.Load())/float64(b.Elapsed().Nanoseconds()), "compares/ns")
})
}
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