Added rotation test for new PageableList code.

examples/widgets/pageable_list.dart

@@ -41,12 +41,6 @@ class PageableListAppState extends State<PageableListApp> {
   ScrollDirection scrollDirection = ScrollDirection.horizontal;
   bool itemsWrap = false;
 
-  void updatePageSize(Size newSize) {
-    setState(() {
-      pageSize = newSize;
-    });
-  }
-
   Widget buildCard(BuildContext context, CardModel cardModel, int index) {
     Widget card = new Card(
       color: cardModel.color,

packages/unit/test/widget/pageable_list_test.dart

@@ -3,17 +3,19 @@
 // found in the LICENSE file.
 
 import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter/rendering.dart';
 import 'package:flutter/widgets.dart';
 import 'package:test/test.dart';
 
-const Size pageSize = const Size(800.0, 600.0);
+Size pageSize = new Size(600.0, 300.0);
 const List<int> defaultPages = const <int>[0, 1, 2, 3, 4, 5];
+final List<GlobalKey> globalKeys = defaultPages.map((_) => new GlobalKey()).toList();
 int currentPage = null;
 bool itemsWrap = false;
 
 Widget buildPage(BuildContext context, int page, int index) {
   return new Container(
-    key: new ValueKey<int>(page),
+    key: globalKeys[page],
     width: pageSize.width,
     height: pageSize.height,
     child: new Text(page.toString())
@@ -21,15 +23,20 @@ Widget buildPage(BuildContext context, int page, int index) {
 }
 
 Widget buildFrame({ List<int> pages: defaultPages }) {
-  // The test framework forces the frame (and so the PageableList)
-  // to be 800x600. The pageSize constant reflects this.
-  return new PageableList<int>(
+  final list = new PageableList<int>(
     items: pages,
     itemBuilder: buildPage,
     itemsWrap: itemsWrap,
     scrollDirection: ScrollDirection.horizontal,
     onPageChanged: (int page) { currentPage = page; }
   );
+
+  // The test framework forces the frame to be 800x600, so we need to create
+  // an outer container where we can change the size.
+  return new Center(
+    child: new Container(
+      width: pageSize.width, height: pageSize.height, child: list)
+  );
 }
 
 void page(WidgetTester tester, Offset offset) {
@@ -57,8 +64,24 @@ void main() {
       expect(currentPage, isNull);
       pageLeft(tester);
       expect(currentPage, equals(1));
+
+      expect(tester.findText('0'), isNull);
+      expect(tester.findText('1'), isNotNull);
+      expect(tester.findText('2'), isNull);
+      expect(tester.findText('3'), isNull);
+      expect(tester.findText('4'), isNull);
+      expect(tester.findText('5'), isNull);
+
       pageRight(tester);
       expect(currentPage, equals(0));
+
+      expect(tester.findText('0'), isNotNull);
+      expect(tester.findText('1'), isNull);
+      expect(tester.findText('2'), isNull);
+      expect(tester.findText('3'), isNull);
+      expect(tester.findText('4'), isNull);
+      expect(tester.findText('5'), isNull);
+
       pageRight(tester);
       expect(currentPage, equals(0));
     });
@@ -118,4 +141,34 @@ void main() {
     });
   });
 
+  test('PageableList resize parent', () {
+    testWidgets((WidgetTester tester) {
+      tester.pumpWidget(new Container());
+      currentPage = null;
+      itemsWrap = true;
+
+      tester.pumpWidget(buildFrame());
+      expect(currentPage, isNull);
+      pageRight(tester);
+      expect(currentPage, equals(5));
+
+      RenderBox box = globalKeys[5].currentContext.findRenderObject();
+      expect(box.size.width, equals(pageSize.width));
+      expect(box.size.height, equals(pageSize.height));
+
+      pageSize = new Size(pageSize.height, pageSize.width);
+      tester.pumpWidget(buildFrame());
+
+      expect(tester.findText('0'), isNull);
+      expect(tester.findText('1'), isNull);
+      expect(tester.findText('2'), isNull);
+      expect(tester.findText('3'), isNull);
+      expect(tester.findText('4'), isNull);
+      expect(tester.findText('5'), isNotNull);
+
+      box = globalKeys[5].currentContext.findRenderObject();
+      expect(box.size.width, equals(pageSize.width));
+      expect(box.size.height, equals(pageSize.height));
+    });
+  });
 }