| // Copyright (c) 2015, 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 empty stream. |
| import "package:expect/expect.dart"; |
| import "dart:async"; |
| import 'package:async_helper/async_helper.dart'; |
| |
| main() { |
| asyncStart(); |
| runTest().whenComplete(asyncEnd); |
| } |
| |
| Future runTest() async { |
| unreachable([a, b]) { |
| throw "UNREACHABLE"; |
| } |
| |
| int tick = 0; |
| ticker() { |
| tick++; |
| } |
| |
| asyncStart(); |
| |
| Stream<int> s = const Stream<int>.empty(); // Is const constructor. |
| Expect.isFalse(s is Stream<String>); // Respects type parameter. |
| StreamSubscription<int> sub = |
| s.listen(unreachable, onError: unreachable, onDone: ticker); |
| Expect.isFalse(sub is StreamSubscription<String>); // Type parameter in sub. |
| |
| // Doesn't do callback in response to listen. |
| Expect.equals(tick, 0); |
| await flushMicrotasks(); |
| // Completes eventually. |
| Expect.equals(tick, 1); |
| |
| // It's a broadcast stream - can listen twice. |
| Expect.isTrue(s.isBroadcast); |
| StreamSubscription<int> sub2 = |
| s.listen(unreachable, onError: unreachable, onDone: unreachable); |
| // respects pause. |
| sub2.pause(); |
| await flushMicrotasks(); |
| // respects cancel. |
| sub2.cancel(); |
| await flushMicrotasks(); |
| Expect.equals(tick, 1); |
| // Still not complete. |
| |
| StreamSubscription<int> sub3 = |
| s.listen(unreachable, onError: unreachable, onDone: ticker); |
| // respects pause. |
| sub3.pause(); |
| Expect.equals(tick, 1); |
| await flushMicrotasks(); |
| // Doesn't complete while paused. |
| Expect.equals(tick, 1); |
| sub3.resume(); |
| await flushMicrotasks(); |
| // Now completed. |
| Expect.equals(tick, 2); |
| |
| asyncEnd(); |
| } |
| |
| Future flushMicrotasks() => new Future.delayed(Duration.zero); |