Adding a reason field to expectAsync and expectAsyncUntil

pkg/unittest/lib/unittest.dart

 // Copyright (c) 2013, 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.
 
 /// Support for writing Dart unit tests.
 ///
 /// For information on installing and importing this library, see the
 /// [unittest package on pub.dartlang.org]
 /// (http://pub.dartlang.org/packages/unittest).
 ///
@@ skipping 279 matching lines @@
 /// [expectAsync] will also ensure that errors that occur within [callback] are
 /// tracked and reported. [callback] should take 0 positional arguments (named
 /// arguments are not supported). [id] can be used to provide more
 /// descriptive error messages if the callback is called more often than
 /// expected. [max] can be used to specify an upper bound on the number of
 /// calls; if this is exceeded the test will fail (or be marked as in error if
 /// it was already complete). A value of 0 for [max] (the default) will set
 /// the upper bound to the same value as [count]; i.e. the callback should be
 /// called exactly [count] times. A value of -1 for [max] will mean no upper
 /// bound.
+///
+/// [reason] is optional and is typically not supplied, as a reason is generated
+/// by the unittest package; if reason is included it is appended to the
+/// generated reason.
 Function expectAsync(Function callback,
-    {int count: 1, int max: 0, String id}) =>
-  new _SpreadArgsHelper(callback, count, max, id).func;
+    {int count: 1, int max: 0, String id, String reason}) =>
+  new _SpreadArgsHelper(callback, count, max, id, reason).func;
 
 /// Indicate that [callback] is expected to be called until [isDone] returns
 /// true. The unittest framework check [isDone] after each callback and only
 /// when it returns true will it continue with the following test. Using
 /// [expectAsyncUntil] will also ensure that errors that occur within
 /// [callback] are tracked and reported. [callback] should take 0 positional
 /// arguments (named arguments are not supported). [id] can be used to
 /// identify the callback in error messages (for example if it is called
 /// after the test case is complete).
-Function expectAsyncUntil(Function callback, bool isDone(), {String id}) =>
-    new _SpreadArgsHelper(callback, 0, -1, id, isDone: isDone).func;
+///
+/// [reason] is optional and is typically not supplied, as a reason is generated
+/// by the unittest package; if reason is included it is appended to the
+/// generated reason.
+Function expectAsyncUntil(Function callback, bool isDone(),
+    {String id, String reason}) =>
+  new _SpreadArgsHelper(callback, 0, -1, id, reason, isDone: isDone).func;
 
 /// Creates a new named group of tests. Calls to group() or test() within the
 /// body of the function passed to this will inherit this group's description.
 void group(String description, void body()) {
   ensureInitialized();
   _requireNotRunning();
   _currentContext = new _GroupContext(_currentContext, description);
   try {
     body();
   } catch (e, trace) {
@@ skipping 231 matching lines @@
 
 /// A flag that controls whether we try to filter out irrelevant frames from
 /// the stack trace. Requires formatStacks to be set.
 bool filterStacks = true;
 
 void _requireNotRunning() {
   if (_currentTestCaseIndex != -1) {
     throw new StateError('Not allowed when tests are running.');
   }
 }