Fix a couple test timeouts.

test/server/utils.dart

 // Copyright (c) 2014, 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.
 
 library json_rpc_2.test.server.util;
 
 import 'dart:async';
 import 'dart:convert';
 
 import 'package:json_rpc_2/json_rpc_2.dart' as json_rpc;
@@ skipping 43 matching lines @@
     'jsonrpc': '2.0',
     'id': id,
     'error': {
       'code': errorCode,
       'message': message,
       'data': data
     }
   })));
 }
 
+/// Returns a matcher that matches [Future]s that never complete.
+Matcher get doesNotComplete => predicate((future) {
+  future.then(expectAsync((_) {
+    // This will never be called. [expectAsync] with `count: 0` ensures that an
+    // error will be thrown when [future] completes.
+  }, count: 0));
+
+  // Make sure there's enough time in the test for [expectAsync] to fail if it's
+  // going to.
+  expect(pumpEventQueue(), completes);
+
+  return true;
+});
+
 /// Returns a matcher that matches a [json_rpc.RpcException] with an
 /// `invalid_params` error code.
 Matcher throwsInvalidParams(String message) {
   return throwsA(predicate((error) {
     expect(error, new isInstanceOf<json_rpc.RpcException>());
     expect(error.code, equals(error_code.INVALID_PARAMS));
     expect(error.message, equals(message));
     return true;
   }));
 }
 
 /// Returns a [Future] that completes after pumping the event queue [times]
 /// times. By default, this should pump the event queue enough times to allow
 /// any code to run, as long as it's not waiting on some external event.
 Future pumpEventQueue([int times = 20]) {
   if (times == 0) return new Future.value();
   // We use a delayed future to allow microtask events to finish. The
   // Future.value or Future() constructors use scheduleMicrotask themselves and
   // would therefore not wait for microtask callbacks that are scheduled after
   // invoking this method.
   return new Future.delayed(Duration.ZERO, () => pumpEventQueue(times - 1));
 }