| // Copyright (c) 2013, 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 |
| |
| /// Test of a common rounding bug. |
| /// |
| /// This bug is common in JavaScript implementations because the ECMA-262 |
| /// specification of JavaScript incorrectly claims: |
| /// |
| /// The value of [:Math.round(x):] is the same as the value of |
| /// [:Math.floor(x+0.5):], except when x is 0 or is less than 0 but greater |
| /// than or equal to -0.5; for these cases [:Math.round(x):] returns 0, but |
| /// [:Math.floor(x+0.5):] returns +0. |
| /// |
| /// However, 0.49999999999999994 + 0.5 is 1 and 9007199254740991 + 0.5 is |
| /// 9007199254740992, so you cannot implement Math.round in terms of |
| /// Math.floor. |
| |
| import 'package:expect/expect.dart'; |
| |
| main() { |
| Expect.equals(0, (0.49999999999999994).round()); |
| Expect.equals(0, (-0.49999999999999994).round()); |
| |
| Expect.equals(9007199254740991, (9007199254740991.0).round()); |
| Expect.equals(-9007199254740991, (-9007199254740991.0).round()); |
| } |