Leaf Petersen
b101a7d002
Change-Id: Ib33169c3e0ffc870915c189404074a1dea472546 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/196548 Reviewed-by: Bob Nystrom <rnystrom@google.com> Commit-Queue: Leaf Petersen <leafp@google.com>
71 lines
1.8 KiB
Dart
71 lines
1.8 KiB
Dart
// Copyright (c) 2015, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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// @dart = 2.9
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// Test empty stream.
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import "package:expect/expect.dart";
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import "dart:async";
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import 'package:async_helper/async_helper.dart';
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main() {
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asyncStart();
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runTest().whenComplete(asyncEnd);
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}
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Future runTest() async {
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unreachable([a, b]) {
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throw "UNREACHABLE";
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}
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int tick = 0;
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ticker() {
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tick++;
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}
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asyncStart();
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Stream<int> s = const Stream<int>.empty(); // Is const constructor.
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Expect.isFalse(s is Stream<String>); // Respects type parameter.
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StreamSubscription<int> sub =
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s.listen(unreachable, onError: unreachable, onDone: ticker);
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Expect.isFalse(sub is StreamSubscription<String>); // Type parameter in sub.
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// Doesn't do callback in response to listen.
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Expect.equals(tick, 0);
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await flushMicrotasks();
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// Completes eventually.
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Expect.equals(tick, 1);
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// It's a broadcast stream - can listen twice.
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Expect.isTrue(s.isBroadcast);
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StreamSubscription<int> sub2 =
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s.listen(unreachable, onError: unreachable, onDone: unreachable);
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// respects pause.
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sub2.pause();
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await flushMicrotasks();
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// respects cancel.
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sub2.cancel();
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await flushMicrotasks();
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Expect.equals(tick, 1);
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// Still not complete.
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StreamSubscription<int> sub3 =
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s.listen(unreachable, onError: unreachable, onDone: ticker);
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// respects pause.
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sub3.pause();
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Expect.equals(tick, 1);
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await flushMicrotasks();
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// Doesn't complete while paused.
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Expect.equals(tick, 1);
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sub3.resume();
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await flushMicrotasks();
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// Now completed.
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Expect.equals(tick, 2);
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asyncEnd();
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}
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Future flushMicrotasks() => new Future.delayed(Duration.zero);
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