LibTest/async/StreamTransformer/StreamTransformer.fromHandlers_A01_t02.dart

/*
 * Copyright (c) 2011, 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.
 */
/**
 * @assertion factory StreamTransformer.fromHandlers({void handleData(S data,
 *   EventSink<T> sink), void handleError(Object error, StackTrace stackTrace,
 *   EventSink<T> sink), void handleDone(EventSink<T> sink)})
 * Creates a StreamTransformer that delegates events to the given functions.
 *
 * @description Checks that handleData() is called on data events and
 * transformed stream gets data that are written to sink.
 * handleError is not provided, so error events are unchanged.
 * @author ilya
 */
import "dart:async";
import "../../../Utils/async_utils.dart";
import "../../../Utils/expect.dart";

main() {
  var s = new Stream.fromIterable([1,2,3,4,5]);
  
  // odd numbers as data events, even numbers as error events
  s = s.map((x) => x.isOdd ? x : throw x);

  var tr = new StreamTransformer.fromHandlers(handleData: (x, sink) {
    sink.add(x+10);
  });
  
  var data = 11;
  var error = 2;

  asyncStart();
  s.transform(tr).listen((x) {
    Expect.equals(data, x);
    data += 2;
  }, onError:(x) {
    Expect.equals(error, x);
    error += 2;
  }, onDone:() {
    asyncEnd();
  });
}