Add StreamChannel.transform().

test/stream_channel_test.dart

+// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:async';
+import 'dart:convert';
+import 'dart:isolate';
+
+import 'package:stream_channel/stream_channel.dart';
+import 'package:test/test.dart';
+
+import 'utils.dart';
+
+void main() {
+  var streamController;
+  var sinkController;
+  var channel;
+  setUp(() {
+    streamController = new StreamController();
+    sinkController = new StreamController();
+    channel = new StreamChannel(
+        streamController.stream, sinkController.sink);
+  });
+
+  test("pipe() pipes data from each channel's stream into the other's sink",
+      () {
+    var otherStreamController = new StreamController();
+    var otherSinkController = new StreamController();
+    var otherChannel = new StreamChannel(
+        otherStreamController.stream, otherSinkController.sink);
+    channel.pipe(otherChannel);
+
+    streamController.add(1);
+    streamController.add(2);
+    streamController.add(3);
+    streamController.close();
+    expect(otherSinkController.stream.toList(), completion(equals([1, 2, 3])));
+
+    otherStreamController.add(4);
+    otherStreamController.add(5);
+    otherStreamController.add(6);
+    otherStreamController.close();
+    expect(sinkController.stream.toList(), completion(equals([4, 5, 6])));
+  });
+
+  test("transform() transforms the channel", () {
+    var transformed = channel.transform(UTF8);
+
+    streamController.add([102, 111, 111, 98, 97, 114]);
+    streamController.close();
+    expect(transformed.stream.toList(), completion(equals(["foobar"])));
+
+    transformed.sink.add("fblthp");
+    transformed.sink.close();
+    expect(sinkController.stream.toList(),
+        completion(equals([[102, 98, 108, 116, 104, 112]])));
+  });
+}