// 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 io_test

import (
	. "io"
	"bytes"
	"crypto/sha1"
	"fmt"
	"strings"
	"testing"
)

func TestMultiWriter(t *testing.T) {
	sha1 := sha1.New()
	sink := new(bytes.Buffer)
	mw := MultiWriter(sha1, sink)

	sourceString := "My input text."
	source := strings.NewReader(sourceString)
	written, err := Copy(mw, source)

	if written != int64(len(sourceString)) {
		t.Errorf("short write of %d, not %d", written, len(sourceString))
	}

	if err != nil {
		t.Errorf("unexpected error: %v", err)
	}

	sha1hex := fmt.Sprintf("%x", sha1.Sum())
	if sha1hex != "01cb303fa8c30a64123067c5aa6284ba7ec2d31b" {
		t.Error("incorrect sha1 value")
	}

	if sink.String() != sourceString {
		t.Error("expected %q; got %q", sourceString, sink.String())
	}
}