blob: a240d3db53896e3a0634ae10e1286eed6bb85161 [file] [log] [blame]
// Copyright (c) 2020, 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_helper/async_minitest.dart';
import 'utils.dart';
main() {
test('pauses execution at yield for at least a microtask', () {
var list = [];
f() async* {
list.add(1);
yield 2;
list.add(3);
yield 4;
list.add(5);
}
var done = Completer();
var sub = f().listen((v) {
if (v == 2) {
expect(list, equals([1]));
} else if (v == 4) {
expect(list, equals([1, 3]));
} else {
fail('Unexpected value $v');
}
}, onDone: () {
expect(list, equals([1, 3, 5]));
done.complete();
});
return done.future;
});
test('pause stops execution at yield', () {
var list = [];
f() async* {
list.add(1);
yield 2;
list.add(3);
yield 4;
list.add(5);
}
var done = Completer();
var sub;
sub = f().listen((v) {
if (v == 2) {
expect(list, equals([1]));
sub.pause();
Timer(ms * 300, () {
expect(list.length, lessThan(3));
sub.resume();
});
} else if (v == 4) {
expect(list, equals([1, 3]));
} else {
fail('Unexpected value $v');
}
}, onDone: () {
expect(list, equals([1, 3, 5]));
done.complete();
});
return done.future;
});
test('pause stops execution at yield 2', () {
var list = [];
f() async* {
int i = 0;
while (true) {
yield i;
list.add(i);
i++;
}
}
int expected = 0;
var done = Completer();
var sub;
sub = f().listen((v) {
expect(v, equals(expected++));
if (v % 5 == 0) {
sub.pause(Future.delayed(ms * 300));
} else if (v == 17) {
sub.cancel();
done.complete();
}
}, onDone: () {
fail('Unexpected done!');
});
return done.future.whenComplete(() {
expect(list.length == 18 || list.length == 19, isTrue);
});
});
}