| // 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 Iterable expand(Iterable f(E element)) |
| * Expands each element of this Iterable into zero or more elements. |
| * The resulting Iterable runs through the elements returned by f for each |
| * element of this, in iteration order. |
| * 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. Function f is |
| * called each time when the object is iterated |
| * @author sgrekhov@unipro.ru |
| */ |
| library expand_A02_t02; |
| import "../../../Utils/expect.dart"; |
| |
| void check(Iterable a) { |
| int count = 0; |
| Iterable expanded = a.expand((element) { |
| count++; |
| return [element]; |
| }); |
| Expect.equals(0, count); |
| expanded.length; |
| Expect.equals(a.length, count); |
| expanded.length; |
| Expect.equals(2 * a.length, count); |
| } |
| |
| test(Iterable create([Iterable content])) { |
| check(create()); |
| check(create([1])); |
| check(create([1, 2])); |
| check(create([1, 2, 2])); |
| check(create([1, 2, 2, 3])); |
| } |