LibTest/async/Stream/transform_A01_t01.test.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 Stream transform(StreamTransformer<T, dynamic> streamTransformer)
/// Chains this stream as the input of the provided StreamTransformer.
/// Returns the result of streamTransformer.bind itself.
/// @description Checks that the data and error events are produced according
/// to transform.
/// @author a.semenov@unipro.ru

library transform_A01_t01;

import "dart:async";
import "../../../Utils/expect.dart";

StreamTransformer<int, int> passThrough = new StreamTransformer.fromHandlers();
StreamTransformer<int, int> doubleDataNegateError =
    new StreamTransformer.fromHandlers(
        handleData: (int event, EventSink<int> sink) {
  sink.add(event);
  sink.add(event);
}, handleError: (Object error, StackTrace st, EventSink<int> sink) {
  sink.addError(-(error as int));
});

void check<T, S>(Stream<T> s, StreamTransformer<T, S> transformer,
    List<S> expectedData, List expectedErrors) {
  AsyncExpect.events(expectedData, expectedErrors, s.transform(transformer));
}

void test(CreateStreamWithErrorsFunction create) {
  check(create([1, 2, 3, 4, 5], defVal: 42), passThrough, [1, 2, 3, 4, 5], []);
  check(create<int>([1, 2, 3, 4, 5], isError: (x) => x.isOdd, defVal: 42), passThrough,
      [2, 4], [1, 3, 5]);
  check(create([1, 2, 3, 4, 5], isError: (x) => true, defVal: 42), passThrough, [],
      [1, 2, 3, 4, 5]);

  check(create([1, 2, 3, 4, 5], defVal: 42), doubleDataNegateError,
      [1, 1, 2, 2, 3, 3, 4, 4, 5, 5], []);
  check(create<int>([1, 2, 3, 4, 5], isError: (x) => x.isOdd, defVal: 42),
      doubleDataNegateError, [2, 2, 4, 4], [-1, -3, -5]);
  check(create([1, 2, 3, 4, 5], isError: (x) => true, defVal: 42), doubleDataNegateError,
      [], [-1, -2, -3, -4, -5]);
}