| // Copyright (c) 2017, 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 Iterable<T> expand<T>(Iterable<T> f(E element)) |
| * ... |
| * The returned Iterable is lazy, and calls f for each element of this every |
| * time it's iterated. |
| * @description Checks that the returned Iterable is lazy, and calls f for each |
| * element of this every time it's iterated. |
| * @author ngl@unipro.ru |
| */ |
| |
| import "dart:typed_data"; |
| import "../../../Utils/expect.dart"; |
| |
| main() { |
| var l = new Int32List.fromList([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]); |
| var counter = 0; |
| var res = l.expand((element) {counter++; return [element * 2];}); |
| Expect.equals(0, counter); |
| |
| var n = 0; |
| for (int i = 0; i < l.length; ++i) { |
| Expect.equals(l[i] * 2, res.elementAt(i)); |
| n += i + 1; |
| Expect.equals(n, counter); |
| } |
| |
| var it = res.iterator; |
| counter = 0; |
| n = 0; |
| while (it.moveNext()) { |
| Expect.equals(l[n++] * 2, it.current); |
| Expect.equals(n, counter); |
| } |
| } |