io: MultiReader and MultiWriter
Little helpers I've found useful.
R=adg, rsc, r, gri
CC=golang-dev
https://golang.org/cl/1764043
diff --git a/src/pkg/io/multi_reader_test.go b/src/pkg/io/multi_reader_test.go
new file mode 100644
index 0000000..7d46396
--- /dev/null
+++ b/src/pkg/io/multi_reader_test.go
@@ -0,0 +1,58 @@
+// 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"
+ "os"
+ "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("bar")
+ mr = MultiReader(r1, r2)
+ buf = make([]byte, 20)
+ tests()
+ }
+ expectRead := func(size int, expected string, eerr os.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, "", os.EOF)
+ })
+ withFooBar(func() {
+ expectRead(4, "foo ", nil)
+ expectRead(1, "b", nil)
+ expectRead(3, "ar", nil)
+ expectRead(1, "", os.EOF)
+ })
+ withFooBar(func() {
+ expectRead(5, "foo ", nil)
+ })
+}
