Revert https://code.google.com/p/dart/source/detail?r=33346

pkg/unittest/lib/unittest.dart

Index: pkg/unittest/lib/unittest.dart
===================================================================
--- pkg/unittest/lib/unittest.dart	(revision 33351)
+++ pkg/unittest/lib/unittest.dart	(working copy)
@@ -325,9 +325,23 @@
  * bound.
  */
 Function expectAsync(Function callback,
-    {int count: 1, int max: 0, String id}) =>
-  new _SpreadArgsHelper(callback, count, max, id);
+                     {int count: 1, int max: 0, String id}) {
+  var minArgs = _minArgs(callback);
 
+  switch(minArgs) {
+    case 0:
+      return new _SpreadArgsHelper(callback, count, max, null, id).invoke0;
+    case 1:
+      return new _SpreadArgsHelper(callback, count, max, null, id).invoke1;
+    case 2:
+      return new _SpreadArgsHelper(callback, count, max, null, id).invoke2;
+    default:
+      // _minArgs throws an argument exception if the arg count is > 2.
+      // this is just for paranoia
+      throw new StateError('Should never get here');
+  }
+}
+
 /**
  * *Deprecated*
  *
@@ -368,9 +382,23 @@
  * 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);
+Function expectAsyncUntil(Function callback, Function isDone, {String id}) {
+  var minArgs = _minArgs(callback);
 
+  switch(minArgs) {
+    case 0:
+      return new _SpreadArgsHelper(callback, 0, -1, isDone, id).invoke0;
+    case 1:
+      return new _SpreadArgsHelper(callback, 0, -1, isDone, id).invoke1;
+    case 2:
+      return new _SpreadArgsHelper(callback, 0, -1, isDone, id).invoke2;
+    default:
+      // _minArgs throws an argument exception if the arg count is > 2.
+      // this is just for paranoia
+      throw new StateError('Should never get here');
+  }
+}
+
 /**
  * *Deprecated*
  *
@@ -742,3 +770,18 @@
     return frame.package != 'unittest' || frame.member != 'TestCase._runTest';
   })).terse.foldFrames((frame) => frame.package == 'unittest' || frame.isCore);
 }
+
+typedef _Func0();
+typedef _Func1(a);
+typedef _Func2(a, b);
+
+/**
+ * Throws an [ArgumentError] if the callback has more than 2 required arguments.
+ */
+int _minArgs(Function callback) {
+  if (callback is _Func0) return 0;
+  if (callback is _Func1) return 1;
+  if (callback is _Func2) return 2;
+  throw new ArgumentError(
+      'The callback argument has more than 2 required arguments.');
+}