platform/sandbox/reactivex/test/transformers/backpressure/buffer_test.dart

118 lines
3 KiB
Dart

import 'dart:async';
import 'package:angel3_reactivex/angel3_reactivex.dart';
import 'package:test/test.dart';
import '../../utils.dart';
Stream<int> getStream(int n) async* {
var k = 0;
while (k < n) {
await Future<void>.delayed(const Duration(milliseconds: 100));
yield k++;
}
}
void main() {
test('Rx.buffer', () async {
await expectLater(
getStream(4).buffer(
Stream<void>.periodic(const Duration(milliseconds: 160)).take(3)),
emitsInOrder(<dynamic>[
const [0, 1],
const [2, 3],
emitsDone
]));
});
test('Rx.buffer.sampleBeforeEvent.shouldEmit', () async {
await expectLater(
Stream.fromFuture(
Future<void>.delayed(const Duration(milliseconds: 200))
.then((_) => 'end')).startWith('start').buffer(
Stream<void>.periodic(const Duration(milliseconds: 40)).take(10)),
emitsInOrder(<dynamic>[
const ['start'], // after 40ms
const <String>[], // 80ms
const <String>[], // 120ms
const <String>[], // 160ms
const ['end'], // done
emitsDone
]));
});
test('Rx.buffer.shouldClose', () async {
final controller = StreamController<int>()
..add(0)
..add(1)
..add(2)
..add(3);
scheduleMicrotask(controller.close);
await expectLater(
controller.stream
.buffer(Stream<void>.periodic(const Duration(seconds: 3)))
.take(1),
emitsInOrder(<dynamic>[
const [0, 1, 2, 3], // done
emitsDone
]));
});
test('Rx.buffer.reusable', () async {
final transformer = BufferStreamTransformer<int>((_) =>
Stream<void>.periodic(const Duration(milliseconds: 160))
.take(3)
.asBroadcastStream());
await expectLater(
getStream(4).transform(transformer),
emitsInOrder(<dynamic>[
const [0, 1],
const [2, 3],
emitsDone
]));
await expectLater(
getStream(4).transform(transformer),
emitsInOrder(<dynamic>[
const [0, 1],
const [2, 3],
emitsDone
]));
});
test('Rx.buffer.asBroadcastStream', () async {
final stream = getStream(4).asBroadcastStream().buffer(
Stream<void>.periodic(const Duration(milliseconds: 160))
.take(10)
.asBroadcastStream());
// listen twice on same stream
await expectLater(
stream,
emitsInOrder(<dynamic>[
const [0, 1],
const [2, 3],
emitsDone
]));
await expectLater(stream, emitsInOrder(<dynamic>[emitsDone]));
});
test('Rx.buffer.error.shouldThrowA', () async {
await expectLater(
Stream<void>.error(Exception())
.buffer(Stream<void>.periodic(const Duration(milliseconds: 160))),
emitsError(isException));
});
test('Rx.buffer.nullable', () {
nullableTest<List<String?>>(
(s) => s.buffer(Stream<void>.empty()),
);
});
}