libgo/go/testing/run_example.go

   1 // Copyright 2019 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 // +build !js
   6
   7 // TODO(@musiol, @odeke-em): re-unify this entire file back into
   8 // example.go when js/wasm gets an os.Pipe implementation
   9 // and no longer needs this separation.
  10
  11 package testing
  12
  13 import (
  14         "fmt"
  15         "io"
  16         "os"
  17         "strings"
  18         "time"
  19 )
  20
  21 func runExample(eg InternalExample) (ok bool) {
  22         if *chatty {
  23                 fmt.Printf("=== RUN   %s\n", eg.Name)
  24         }
  25
  26         // Capture stdout.
  27         stdout := os.Stdout
  28         r, w, err := os.Pipe()
  29         if err != nil {
  30                 fmt.Fprintln(os.Stderr, err)
  31                 os.Exit(1)
  32         }
  33         os.Stdout = w
  34         outC := make(chan string)
  35         go func() {
  36                 var buf strings.Builder
  37                 _, err := io.Copy(&buf, r)
  38                 r.Close()
  39                 if err != nil {
  40                         fmt.Fprintf(os.Stderr, "testing: copying pipe: %v\n", err)
  41                         os.Exit(1)
  42                 }
  43                 outC <- buf.String()
  44         }()
  45
  46         finished := false
  47         start := time.Now()
  48
  49         // Clean up in a deferred call so we can recover if the example panics.
  50         defer func() {
  51                 timeSpent := time.Since(start)
  52
  53                 // Close pipe, restore stdout, get output.
  54                 w.Close()
  55                 os.Stdout = stdout
  56                 out := <-outC
  57
  58                 err := recover()
  59                 ok = eg.processRunResult(out, timeSpent, finished, err)
  60         }()
  61
  62         // Run example.
  63         eg.F()
  64         finished = true
  65         return
  66 }