Add expectAsyncX and expectAsyncUntilX methods, and deprecate the old methods.

test/utils.dart

 // 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 'dart:collection';
 
 import 'package:test/src/backend/declarer.dart';
 import 'package:test/src/backend/group.dart';
 import 'package:test/src/backend/group_entry.dart';
@@ skipping 17 matching lines @@
 final String closureString = (() {}).toString();
 
 // The last state change detected via [expectStates].
 State lastState;
 
 /// Asserts that exactly [states] will be emitted via [liveTest.onStateChange].
 ///
 /// The most recent emitted state is stored in [_lastState].
 void expectStates(LiveTest liveTest, Iterable<State> statesIter) {
   var states = new Queue.from(statesIter);
-  liveTest.onStateChange.listen(expectAsync((state) {
+  liveTest.onStateChange.listen(expectAsync1((state) {
     lastState = state;
     expect(state, equals(states.removeFirst()));
   }, count: states.length, max: states.length));
 }
 
 /// Asserts that errors will be emitted via [liveTest.onError] that match
 /// [validators], in order.
 void expectErrors(LiveTest liveTest, Iterable<Function> validatorsIter) {
   var validators = new Queue.from(validatorsIter);
-  liveTest.onError.listen(expectAsync((error) {
+  liveTest.onError.listen(expectAsync1((error) {
     validators.removeFirst()(error.error);
   }, count: validators.length, max: validators.length));
 }
 
 /// Asserts that [liveTest] will have a single failure with message `"oh no"`.
 void expectSingleFailure(LiveTest liveTest) {
   expectStates(liveTest, [
     const State(Status.running, Result.success),
     const State(Status.complete, Result.failure)
   ]);
@@ skipping 253 matching lines @@
     new RunnerSuite(
         const PluginEnvironment(),
         new SuiteConfiguration(runSkipped: runSkipped),
         declarer.build())
   ]);
 }
 
 /// Returns a [RunnerSuite] with a default environment and configuration.
 RunnerSuite runnerSuite(Group root) =>
     new RunnerSuite(const PluginEnvironment(), SuiteConfiguration.empty, root);