| // Copyright (c) 2020, 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. |
| |
| import "dart:collection"; |
| import "package:expect/expect.dart"; |
| import 'cast_helper.dart'; |
| |
| void main() { |
| testDowncast(); |
| testUpcast(); |
| testRegression(); |
| } |
| |
| void testDowncast() { |
| var list = new List<C>.from(elements); |
| var dList = List.castFrom<C, D>(list); |
| |
| Expect.throws(() => dList.first); // C is not D. |
| Expect.equals(d, dList[1]); |
| Expect.throws(() => dList[2]); // E is not D. |
| Expect.equals(f, dList[3]); |
| Expect.equals(null, dList.last); |
| |
| Expect.throws(() => dList.toList()); |
| |
| // Setting works. |
| dList[2] = d; |
| Expect.equals(d, dList[2]); |
| } |
| |
| void testUpcast() { |
| var list2 = new List<C>.from(elements); |
| var dList2 = List.castFrom<C, Object>(list2); |
| Expect.listEquals(elements, dList2); |
| Expect.throws(() => dList2[2] = new Object()); // Cannot set non-C. |
| Expect.listEquals(elements, dList2); |
| } |
| |
| void testRegression() { |
| var numList = <num>[4, 3, 2, 1]; |
| var intList = numList.cast<int>(); |
| intList.sort(null); |
| Expect.listEquals([1, 2, 3, 4], numList); |
| Expect.listEquals([1, 2, 3, 4], intList); |
| } |