Source file src/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		start := time.Now()
    47	
    48		// Clean up in a deferred call so we can recover if the example panics.
    49		defer func() {
    50			timeSpent := time.Since(start)
    51	
    52			// Close pipe, restore stdout, get output.
    53			w.Close()
    54			os.Stdout = stdout
    55			out := <-outC
    56	
    57			err := recover()
    58			ok = eg.processRunResult(out, timeSpent, err)
    59		}()
    60	
    61		// Run example.
    62		eg.F()
    63		return
    64	}
    65	

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