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// 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 (
"bytes"
"crypto/sha1"
"fmt"
. "io"
"io/ioutil"
"strings"
"testing"
)
func TestMultiReader(t *testing.T) {
var mr Reader
var buf []byte
nread := 0
withFooBar := func(tests func()) {
r1 := strings.NewReader("foo ")
r2 := strings.NewReader("")
r3 := strings.NewReader("bar")
mr = MultiReader(r1, r2, r3)
buf = make([]byte, 20)
tests()
}
expectRead := func(size int, expected string, eerr error) {
nread++
n, gerr := mr.Read(buf[0:size])
if n != len(expected) {
t.Errorf("#%d, expected %d bytes; got %d",
nread, len(expected), n)
}
got := string(buf[0:n])
if got != expected {
t.Errorf("#%d, expected %q; got %q",
nread, expected, got)
}
if gerr != eerr {
t.Errorf("#%d, expected error %v; got %v",
nread, eerr, gerr)
}
buf = buf[n:]
}
withFooBar(func() {
expectRead(2, "fo", nil)
expectRead(5, "o ", nil)
expectRead(5, "bar", nil)
expectRead(5, "", EOF)
})
withFooBar(func() {
expectRead(4, "foo ", nil)
expectRead(1, "b", nil)
expectRead(3, "ar", nil)
expectRead(1, "", EOF)
})
withFooBar(func() {
expectRead(5, "foo ", nil)
})
}
func TestMultiWriter(t *testing.T) {
sink := new(bytes.Buffer)
// Hide bytes.Buffer's WriteString method:
testMultiWriter(t, struct {
Writer
fmt.Stringer
}{sink, sink})
}
func TestMultiWriter_String(t *testing.T) {
testMultiWriter(t, new(bytes.Buffer))
}
// test that a multiWriter.WriteString calls results in at most 1 allocation,
// even if multiple targets don't support WriteString.
func TestMultiWriter_WriteStringSingleAlloc(t *testing.T) {
var sink1, sink2 bytes.Buffer
type simpleWriter struct { // hide bytes.Buffer's WriteString
Writer
}
mw := MultiWriter(simpleWriter{&sink1}, simpleWriter{&sink2})
allocs := int(testing.AllocsPerRun(1000, func() {
WriteString(mw, "foo")
}))
if allocs != 1 {
t.Errorf("num allocations = %d; want 1", allocs)
}
}
type writeStringChecker struct{ called bool }
func (c *writeStringChecker) WriteString(s string) (n int, err error) {
c.called = true
return len(s), nil
}
func (c *writeStringChecker) Write(p []byte) (n int, err error) {
return len(p), nil
}
func TestMultiWriter_StringCheckCall(t *testing.T) {
var c writeStringChecker
mw := MultiWriter(&c)
WriteString(mw, "foo")
if !c.called {
t.Error("did not see WriteString call to writeStringChecker")
}
}
func testMultiWriter(t *testing.T, sink interface {
Writer
fmt.Stringer
}) {
sha1 := sha1.New()
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(nil))
if sha1hex != "01cb303fa8c30a64123067c5aa6284ba7ec2d31b" {
t.Error("incorrect sha1 value")
}
if sink.String() != sourceString {
t.Errorf("expected %q; got %q", sourceString, sink.String())
}
}
// Test that MultiReader copies the input slice and is insulated from future modification.
func TestMultiReaderCopy(t *testing.T) {
slice := []Reader{strings.NewReader("hello world")}
r := MultiReader(slice...)
slice[0] = nil
data, err := ioutil.ReadAll(r)
if err != nil || string(data) != "hello world" {
t.Errorf("ReadAll() = %q, %v, want %q, nil", data, err, "hello world")
}
}
// Test that MultiWriter copies the input slice and is insulated from future modification.
func TestMultiWriterCopy(t *testing.T) {
var buf bytes.Buffer
slice := []Writer{&buf}
w := MultiWriter(slice...)
slice[0] = nil
n, err := w.Write([]byte("hello world"))
if err != nil || n != 11 {
t.Errorf("Write(`hello world`) = %d, %v, want 11, nil", n, err)
}
if buf.String() != "hello world" {
t.Errorf("buf.String() = %q, want %q", buf.String(), "hello world")
}
}