1 files changed, 115 insertions, 0 deletions
diff --git a/src/io/multi_test.go b/src/io/multi_test.go
new file mode 100644
index 000000000..56c6769a9
--- /dev/null
+++ b/src/io/multi_test.go
@@ -0,0 +1,115 @@
+// 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) {
+	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(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")
+	}
+}