libgo/go/testing/benchmark_test.go

   1 // Copyright 2013 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 package testing_test
   6
   7 import (
   8         "bytes"
   9         "runtime"
  10         "sync/atomic"
  11         "testing"
  12         "text/template"
  13 )
  14
  15 var roundDownTests = []struct {
  16         v, expected int
  17 }{
  18         {1, 1},
  19         {9, 1},
  20         {10, 10},
  21         {11, 10},
  22         {100, 100},
  23         {101, 100},
  24         {999, 100},
  25         {1000, 1000},
  26         {1001, 1000},
  27 }
  28
  29 func TestRoundDown10(t *testing.T) {
  30         for _, tt := range roundDownTests {
  31                 actual := testing.RoundDown10(tt.v)
  32                 if tt.expected != actual {
  33                         t.Errorf("roundDown10(%d): expected %d, actual %d", tt.v, tt.expected, actual)
  34                 }
  35         }
  36 }
  37
  38 var roundUpTests = []struct {
  39         v, expected int
  40 }{
  41         {0, 1},
  42         {1, 1},
  43         {2, 2},
  44         {5, 5},
  45         {9, 10},
  46         {999, 1000},
  47         {1000, 1000},
  48         {1400, 2000},
  49         {1700, 2000},
  50         {4999, 5000},
  51         {5000, 5000},
  52         {5001, 10000},
  53 }
  54
  55 func TestRoundUp(t *testing.T) {
  56         for _, tt := range roundUpTests {
  57                 actual := testing.RoundUp(tt.v)
  58                 if tt.expected != actual {
  59                         t.Errorf("roundUp(%d): expected %d, actual %d", tt.v, tt.expected, actual)
  60                 }
  61         }
  62 }
  63
  64 func TestRunParallel(t *testing.T) {
  65         testing.Benchmark(func(b *testing.B) {
  66                 procs := uint32(0)
  67                 iters := uint64(0)
  68                 b.SetParallelism(3)
  69                 b.RunParallel(func(pb *testing.PB) {
  70                         atomic.AddUint32(&procs, 1)
  71                         for pb.Next() {
  72                                 atomic.AddUint64(&iters, 1)
  73                         }
  74                 })
  75                 if want := uint32(3 * runtime.GOMAXPROCS(0)); procs != want {
  76                         t.Errorf("got %v procs, want %v", procs, want)
  77                 }
  78                 if iters != uint64(b.N) {
  79                         t.Errorf("got %v iters, want %v", iters, b.N)
  80                 }
  81         })
  82 }
  83
  84 func TestRunParallelFail(t *testing.T) {
  85         testing.Benchmark(func(b *testing.B) {
  86                 b.RunParallel(func(pb *testing.PB) {
  87                         // The function must be able to log/abort
  88                         // w/o crashing/deadlocking the whole benchmark.
  89                         b.Log("log")
  90                         b.Error("error")
  91                 })
  92         })
  93 }
  94
  95 func ExampleB_RunParallel() {
  96         // Parallel benchmark for text/template.Template.Execute on a single object.
  97         testing.Benchmark(func(b *testing.B) {
  98                 templ := template.Must(template.New("test").Parse("Hello, {{.}}!"))
  99                 // RunParallel will create GOMAXPROCS goroutines
 100                 // and distribute work among them.
 101                 b.RunParallel(func(pb *testing.PB) {
 102                         // Each goroutine has its own bytes.Buffer.
 103                         var buf bytes.Buffer
 104                         for pb.Next() {
 105                                 // The loop body is executed b.N times total across all goroutines.
 106                                 buf.Reset()
 107                                 templ.Execute(&buf, "World")
 108                         }
 109                 })
 110         })
 111 }