platform/sandbox/reactivex/test/transformers/scan_test.dart
2024-11-12 01:00:05 -07:00

85 lines
2.4 KiB
Dart

import 'dart:async';
import 'package:angel3_reactivex/angel3_reactivex.dart';
import 'package:test/test.dart';
import '../utils.dart';
void main() {
test('Rx.scan', () async {
const expectedOutput = [1, 3, 6, 10];
var count = 0;
Stream.fromIterable(const [1, 2, 3, 4])
.scan<int>((acc, value, index) => acc + value, 0)
.listen(expectAsync1((result) {
expect(expectedOutput[count++], result);
}, count: expectedOutput.length));
});
test('Rx.scan.nullable', () {
nullableTest<String?>(
(s) => s.scan((acc, value, index) => acc, null),
);
expect(
Stream.fromIterable(const [1, 2, 3, 4])
.scan<int?>((acc, value, index) => (acc ?? 0) + value, null)
.cast<int>(),
emitsInOrder(<int>[1, 3, 6, 10]),
);
});
test('Rx.scan.reusable', () async {
final transformer =
ScanStreamTransformer<int, int>((acc, value, index) => acc + value, 0);
const expectedOutput = [1, 3, 6, 10];
var countA = 0, countB = 0;
Stream.fromIterable(const [1, 2, 3, 4])
.transform(transformer)
.listen(expectAsync1((result) {
expect(expectedOutput[countA++], result);
}, count: expectedOutput.length));
Stream.fromIterable(const [1, 2, 3, 4])
.transform(transformer)
.listen(expectAsync1((result) {
expect(expectedOutput[countB++], result);
}, count: expectedOutput.length));
});
test('Rx.scan.asBroadcastStream', () async {
final stream = Stream.fromIterable(const [1, 2, 3, 4])
.asBroadcastStream()
.scan<int>((acc, value, index) => acc + value, 0);
// listen twice on same stream
stream.listen(null);
stream.listen(null);
// code should reach here
await expectLater(true, true);
});
test('Rx.scan.error.shouldThrow', () async {
final streamWithError = Stream.fromIterable(const [1, 2, 3, 4])
.scan((acc, value, index) => throw StateError('oh noes!'), 0);
streamWithError.listen(null,
onError: expectAsync2((StateError e, StackTrace s) {
expect(e, isStateError);
}, count: 4));
});
test('Rx.scan accidental broadcast', () async {
final controller = StreamController<int>();
final stream =
controller.stream.scan<int>((acc, value, index) => acc + value, 0);
stream.listen(null);
expect(() => stream.listen(null), throwsStateError);
controller.add(1);
});
}