blob: 2fa1b92ceba04c7d3724fe70e134e0b0eb0522c9 [file] [log] [blame]
// 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.
/// Helper utilities for testing.
import 'dart:async';
import 'package:async/async.dart';
import 'package:test/test.dart';
/// A zero-millisecond timer should wait until after all microtasks.
Future flushMicrotasks() => Future.delayed(Duration.zero);
typedef OptionalArgAction = void Function([dynamic a, dynamic b]);
/// A generic unreachable callback function.
///
/// Returns a function that fails the test if it is ever called.
OptionalArgAction unreachable(String name) =>
([a, b]) => fail('Unreachable: $name');
/// A matcher that runs a callback in its own zone and asserts that that zone
/// emits an error that matches [matcher].
Matcher throwsZoned(Matcher matcher) => predicate((void Function() callback) {
var firstError = true;
runZonedGuarded(
callback,
expectAsync2((error, stackTrace) {
if (firstError) {
expect(error, matcher);
firstError = false;
} else {
registerException(error, stackTrace);
}
}, max: -1));
return true;
});
/// A matcher that runs a callback in its own zone and asserts that that zone
/// emits a [TypeError].
final throwsZonedTypeError = throwsZoned(TypeMatcher<TypeError>());
/// A matcher that matches a callback or future that throws a [TypeError].
final throwsTypeError = throwsA(TypeMatcher<TypeError>());
/// A badly behaved stream which throws if it's ever listened to.
///
/// Can be used to test cases where a stream should not be used.
class UnusableStream<T> extends Stream<T> {
@override
StreamSubscription<T> listen(void Function(T event)? onData,
{Function? onError, void Function()? onDone, bool? cancelOnError}) {
throw UnimplementedError('Gotcha!');
}
}
/// A dummy [StreamSink] for testing the routing of the [done] and [close]
/// futures.
///
/// The [completer] field allows the user to control the future returned by
/// [done] and [close].
class CompleterStreamSink<T> implements StreamSink<T> {
final completer = Completer();
@override
Future get done => completer.future;
@override
void add(T event) {}
@override
void addError(Object error, [StackTrace? stackTrace]) {}
@override
Future addStream(Stream<T> stream) async {}
@override
Future close() => completer.future;
}
/// A [StreamSink] that collects all events added to it as results.
///
/// This is used for testing code that interacts with sinks.
class TestSink<T> implements StreamSink<T> {
/// The results corresponding to events that have been added to the sink.
final results = <Result<T>>[];
/// Whether [close] has been called.
bool get isClosed => _isClosed;
var _isClosed = false;
@override
Future get done => _doneCompleter.future;
final _doneCompleter = Completer();
final void Function() _onDone;
/// Creates a new sink.
///
/// If [onDone] is passed, it's called when the user calls [close]. Its result
/// is piped to the [done] future.
TestSink({void Function()? onDone}) : _onDone = onDone ?? (() {});
@override
void add(T event) {
results.add(Result<T>.value(event));
}
@override
void addError(Object error, [StackTrace? stackTrace]) {
results.add(Result<T>.error(error, stackTrace));
}
@override
Future addStream(Stream<T> stream) {
var completer = Completer.sync();
stream.listen(add, onError: addError, onDone: completer.complete);
return completer.future;
}
@override
Future close() {
_isClosed = true;
_doneCompleter.complete(Future.microtask(_onDone));
return done;
}
}