LibTest/async/Stream/expand_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.

// @dart = 2.9

/// @assertion Stream<S> expand<S>(Iterable<S> convert(T value))
///    Creates a new stream from this stream that converts each element into zero
/// or more events.
///    Each incoming event is converted to an Iterable of new events, and each of
/// these new events are then sent by the returned stream in order.
/// @description Checks that returned stream produces all the values generated by
/// the convert function.
/// @author a.semenov@unipro.ru

library expand_A01_t01;
import "dart:async";
import "../../../Utils/expect.dart";

void check<T,S>(Stream<T> s, Iterable<S>convert(T value), List<S> expected) {
  AsyncExpect.data(expected, s.expand(convert));
}

void test(CreateStreamFunction create) {
  check(create([]), (value) => [], []);
  check(create([]), (value) => [1], []);

  check(create([1,2,3]), (value) => [], []);
  check(create([1,2,3]), (value) => [1], [1,1,1]);
  check(create([1,2,3]), (value) => [value], [1,2,3]);
  check(create([1,2,3]), (v) => [v,v], [1,1,2,2,3,3]);
  check(create([1,2,3]), (v) => [null,v], [null,1,null,2,null,3]);

  check(create([[1,2,3],[4,5]]), (value) => value, [1,2,3,4,5]);
}