golang export_test 代码
文件路径：/src/flag/export_test.go
// Copyright 2010 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 flag
import (
"io"
"os"
)
// Additional routines compiled into the package only during testing.
var DefaultUsage = Usage
// ResetForTesting clears all flag state and sets the usage function as directed.
// After calling ResetForTesting, parse errors in flag handling will not
// exit the program.
func ResetForTesting(usage func()) {
CommandLine = NewFlagSet(os.Args[0], ContinueOnError)
CommandLine.SetOutput(io.Discard)
CommandLine.Usage = commandLineUsage
Usage = usage
}