LibTest/async/Stream/lastWhere_A01_t02.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.

// @dart = 2.9

/// @assertion Future<T> lastWhere (bool test(T element),
///     {@deprecated dynamic defaultValue(),  T orElse()})
///
/// Finds the last element in this stream matching test.
///
/// If this stream emits an error, the returned future is completed with that
/// error, and processing stops.
///
/// Otherwise as firstWhere, except that the last matching element is found
/// instead of the first. That means that a non-error result cannot be provided
/// before this stream is done.
///
/// The defaultValue parameter is deprecated, and orElse should be used instead.
/// @description Checks that if element is found, it is passed to the resulting
/// future. [orElse] is provided.
/// @author a.semenov@unipro.ru

library lastWhere_A01_t02;
import "dart:async";
import "../../../Utils/expect.dart";

void check<T>(Stream<T> s, bool test(T element), T expected) {
  bool orElseCalled = false;
  asyncStart();
  s.lastWhere(test, orElse:() {orElseCalled = true;})
   .then((T actual){
     Expect.equals(expected, actual);
     Expect.isFalse(orElseCalled);
     asyncEnd();
   });
}

void test(CreateStreamFunction create) {
  check(create<int>([1, 2, 3]), (int element) => true, 3);
  check(create<int>([1, 2, 3]), (int element) => element != null, 3);
  check(create<int>([1, 2, 3, null]), (int element) => element == null, null);
  check(create<int>([1, 2, 3]), (int element) => element > 0, 3);
  check(create<int>(new Iterable<int>.generate(10, (int index) => index * 5)),
      (int element) => element != 30, 45);
  check(create<int>(new Iterable<int>.generate(10, (int index) => index * 5)),
      (int element) => element == 30, 30);
}