New expectation functions plus convert old tests to use these.

tests/isolate/mandel_isolate_test.dart

Index: tests/isolate/mandel_isolate_test.dart
===================================================================
--- tests/isolate/mandel_isolate_test.dart	(revision 8345)
+++ tests/isolate/mandel_isolate_test.dart	(working copy)
@@ -14,7 +14,7 @@
   test("Render Mandelbrot in parallel", () {
     final state = new MandelbrotState();
     state._validated.future.then(expectAsync1((result) {
-      expect(result).isTrue();
+      expect(result, isTrue);
     }));
     for (int i = 0; i < Math.min(ISOLATES, N); i++) state.startClient(i);
   });