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Source file src/testing/run_example.go

Documentation: testing

     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  //go:build !js
     6  // +build !js
     7  
     8  // TODO(@musiol, @odeke-em): re-unify this entire file back into
     9  // example.go when js/wasm gets an os.Pipe implementation
    10  // and no longer needs this separation.
    11  
    12  package testing
    13  
    14  import (
    15  	"fmt"
    16  	"io"
    17  	"os"
    18  	"strings"
    19  	"time"
    20  )
    21  
    22  func runExample(eg InternalExample) (ok bool) {
    23  	if *chatty {
    24  		fmt.Printf("=== RUN   %s\n", eg.Name)
    25  	}
    26  
    27  	// Capture stdout.
    28  	stdout := os.Stdout
    29  	r, w, err := os.Pipe()
    30  	if err != nil {
    31  		fmt.Fprintln(os.Stderr, err)
    32  		os.Exit(1)
    33  	}
    34  	os.Stdout = w
    35  	outC := make(chan string)
    36  	go func() {
    37  		var buf strings.Builder
    38  		_, err := io.Copy(&buf, r)
    39  		r.Close()
    40  		if err != nil {
    41  			fmt.Fprintf(os.Stderr, "testing: copying pipe: %v\n", err)
    42  			os.Exit(1)
    43  		}
    44  		outC <- buf.String()
    45  	}()
    46  
    47  	finished := false
    48  	start := time.Now()
    49  
    50  	// Clean up in a deferred call so we can recover if the example panics.
    51  	defer func() {
    52  		timeSpent := time.Since(start)
    53  
    54  		// Close pipe, restore stdout, get output.
    55  		w.Close()
    56  		os.Stdout = stdout
    57  		out := <-outC
    58  
    59  		err := recover()
    60  		ok = eg.processRunResult(out, timeSpent, finished, err)
    61  	}()
    62  
    63  	// Run example.
    64  	eg.F()
    65  	finished = true
    66  	return
    67  }
    68  

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