Make it possible to test that the stock app doesn't crash on startup and paints the basic scaffold …

sky/tests/raw/render_flex.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import '../resources/third_party/unittest/unittest.dart';
-import '../resources/unit.dart';
-import '../resources/display_list.dart';
 import 'dart:sky' as sky;
+
 import 'package:sky/framework/app.dart';
 import 'package:sky/framework/rendering/block.dart';
 import 'package:sky/framework/rendering/box.dart';
 import 'package:sky/framework/rendering/flex.dart';
 
+import '../resources/display_list.dart';
+import '../resources/third_party/unittest/unittest.dart';
+import '../resources/unit.dart';
+
 class RenderSolidColor extends RenderDecoratedBox {
   final sky.Size desiredSize;
   final sky.Color backgroundColor;
 
   RenderSolidColor(sky.Color backgroundColor, { this.desiredSize: sky.Size.infinite })
       : backgroundColor = backgroundColor,
         super(decoration: new BoxDecoration(backgroundColor: backgroundColor)) {
   }
 
   double getMinIntrinsicWidth(BoxConstraints constraints) {
@@ skipping 17 matching lines @@
   }
 
   void handleEvent(sky.Event event, BoxHitTestEntry entry) {
     if (event.type == 'pointerdown')
       decoration = new BoxDecoration(backgroundColor: const sky.Color(0xFFFF0000));
     else if (event.type == 'pointerup')
       decoration = new BoxDecoration(backgroundColor: backgroundColor);
   }
 }
 
-TestApp app;
-
 void main() {
   initUnit();
 
   test("should flex", () {
     RenderFlex flexRoot = new RenderFlex(direction: FlexDirection.vertical);
 
     RenderDecoratedBox root = new RenderDecoratedBox(
       decoration: new BoxDecoration(backgroundColor: const sky.Color(0xFF000000)),
       child: flexRoot
     );
@@ skipping 29 matching lines @@
     addFlexChildSolidColor(row, const sky.Color(0x77FF00FF), flex: 1);
     addFlexChildSolidColor(row, const sky.Color(0xFF0000FF), flex: 2);
 
     var decoratedRow = new RenderDecoratedBox(
       decoration: new BoxDecoration(backgroundColor: const sky.Color(0xFF333333)),
       child: row
     );
 
     flexRoot.add(decoratedRow);
     decoratedRow.parentData.flex = 3;
-    app = new TestApp(root);
+
+    new TestRenderView(root);
 
     expect(root.size.width, equals(sky.view.width));
     expect(root.size.height, equals(sky.view.height));
     expect(renderBlock.size.width, equals(sky.view.width - 20.0));
 
   });
 }