You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: stdio_test.go
    path of file: ./repos/gccrs/libgo/misc/cgo/stdio
    
    the code of the file until where you have to start completion: // Copyright 2019 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 stdio_test

import (
	"bytes"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"testing"
)

func TestMain(m *testing.M) {
	log.SetFlags(log.Lshortfile)
	os.Exit(testMain(m))
}

func testMain(m *testing.M) int {
	GOPATH, err := os.MkdirTemp("", "cgostdio")
	if err != nil {
		log.Panic(err)
	}

    
func testMain(m *testing.M) int {
	GOPATH, err := os.MkdirTemp("", "cgostdio")
	if err != nil {
		log.Panic(err)
	}
	defer os.RemoveAll(GOPATH)
	os.Setenv("GOPATH", GOPATH)

	// Copy testdata into GOPATH/src/cgostdio, along with a go.mod file
	// declaring the same path.
	modRoot := filepath.Join(GOPATH, "src", "cgostdio")
	if err := overlayDir(modRoot, "testdata"); err != nil {
		log.Panic(err)
	}
	if err := os.Chdir(modRoot); err != nil {
		log.Panic(err)
	}
	os.Setenv("PWD", modRoot)
	if err := os.WriteFile("go.mod", []byte("module cgostdio\n"), 0666); err != nil {
		log.Panic(err)
	}

	return m.Run()
}