| // 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. |
| |
| import "dart:async"; |
| |
| import "package:async/async.dart"; |
| import "package:test/test.dart"; |
| |
| import "utils.dart"; |
| |
| main() { |
| test("disallows a null callback", () { |
| expect(() => new LazyStream(null), throwsArgumentError); |
| }); |
| |
| test("calls the callback when the stream is listened", () async { |
| var callbackCalled = false; |
| var stream = new LazyStream(expectAsync0(() { |
| callbackCalled = true; |
| return new Stream.empty(); |
| })); |
| |
| await flushMicrotasks(); |
| expect(callbackCalled, isFalse); |
| |
| stream.listen(null); |
| expect(callbackCalled, isTrue); |
| }); |
| |
| test("calls the callback when the stream is listened", () async { |
| var callbackCalled = false; |
| var stream = new LazyStream(expectAsync0(() { |
| callbackCalled = true; |
| return new Stream.empty(); |
| })); |
| |
| await flushMicrotasks(); |
| expect(callbackCalled, isFalse); |
| |
| stream.listen(null); |
| expect(callbackCalled, isTrue); |
| }); |
| |
| test("forwards to a synchronously-provided stream", () async { |
| var controller = new StreamController<int>(); |
| var stream = new LazyStream(expectAsync0(() => controller.stream)); |
| |
| var events = []; |
| stream.listen(events.add); |
| |
| controller.add(1); |
| await flushMicrotasks(); |
| expect(events, equals([1])); |
| |
| controller.add(2); |
| await flushMicrotasks(); |
| expect(events, equals([1, 2])); |
| |
| controller.add(3); |
| await flushMicrotasks(); |
| expect(events, equals([1, 2, 3])); |
| |
| controller.close(); |
| }); |
| |
| test("forwards to an asynchronously-provided stream", () async { |
| var controller = new StreamController<int>(); |
| var stream = new LazyStream(expectAsync0(() async => controller.stream)); |
| |
| var events = []; |
| stream.listen(events.add); |
| |
| controller.add(1); |
| await flushMicrotasks(); |
| expect(events, equals([1])); |
| |
| controller.add(2); |
| await flushMicrotasks(); |
| expect(events, equals([1, 2])); |
| |
| controller.add(3); |
| await flushMicrotasks(); |
| expect(events, equals([1, 2, 3])); |
| |
| controller.close(); |
| }); |
| |
| test("a lazy stream can't be listened to multiple times", () { |
| var stream = new LazyStream(expectAsync0(() => new Stream.empty())); |
| expect(stream.isBroadcast, isFalse); |
| |
| stream.listen(null); |
| expect(() => stream.listen(null), throwsStateError); |
| expect(() => stream.listen(null), throwsStateError); |
| }); |
| |
| test("a lazy stream can't be listened to from within its callback", () { |
| LazyStream stream; |
| stream = new LazyStream(expectAsync0(() { |
| expect(() => stream.listen(null), throwsStateError); |
| return new Stream.empty(); |
| })); |
| stream.listen(null); |
| }); |
| } |