| // Copyright (c) 2011, 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 Future fold(initialValue, combine(previous, T element)) |
| /// Reduces a sequence of values by repeatedly applying combine. |
| /// @description Checks that if the stream contains no elements, the combine method |
| /// is not called and the future returns initialValue. |
| /// @note undocumented |
| /// @author kaigorodov |
| |
| import "dart:async"; |
| import "../../../Utils/expect.dart"; |
| import "IsolateStream.dart" as IsolateStream; |
| |
| void check( |
| Iterable data, initialValue, combine(previous, var element), var expected) { |
| Stream s = IsolateStream.fromIterable(data); |
| asyncStart(); |
| Future f = s.fold(initialValue, combine); |
| f.then((var actual) { |
| Expect.equals(expected, actual); |
| asyncEnd(); |
| }); |
| } |
| |
| main() { |
| check([], null, (p, e) {Expect.fail("combine musn't be called");}, null); |
| check([], 777, (p, e) {Expect.fail("combine musn't be called");}, 777); |
| check([], "", (p, e) {Expect.fail("combine musn't be called");}, ""); |
| } |