| // Copyright (c) 2016, 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 void shuffle([Random random]) |
| /// Shuffles the elements of this list randomly. |
| /// @description Checks that this method shuffles the elements of this list |
| /// randomly. |
| /// @author sgrekhov@unipro.ru |
| |
| library shuffle_A01_t01; |
| |
| import "../../../Utils/expect.dart"; |
| |
| bool isOrderChanged(List list, List sl) { |
| Expect.equals(list.length, sl.length); |
| bool moved = false; |
| for (int i = 0; i < list.length; i++) { |
| bool found = false; |
| for (int j = 0; j < list.length; j++) { |
| if (list[i] == sl[j]) { |
| found = true; |
| if (i != j) moved = true; |
| break; |
| } |
| } |
| Expect.isTrue(found, "Element ${list[i]} not found in shuffled list"); |
| } |
| return moved; |
| } |
| |
| |
| test(List<E> create<E>([int length, E fill])) { |
| List initial = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]; |
| var counter = 0; |
| for (int i = 0; i < 10; i++) { |
| var sl = create(); |
| sl.addAll(initial); |
| sl.shuffle(); |
| |
| if (!isOrderChanged(initial, sl)) { |
| counter++; |
| } |
| } |
| /* We allow a couple of shuffles return data in the same order */ |
| Expect.isTrue(counter < 3); |
| } |