Merge pull request #1447 from abarth/reactivate

GlobalKeys should preserve state across tree mutations

packages/unit/test/widget/reparent_state_test.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 'package:sky/widgets.dart';
+import 'package:test/test.dart';
+
+import 'widget_tester.dart';
+
+class StateMarker extends StatefulComponent {
+  StateMarker({ Key key, this.child }) : super(key: key);
+
+  final Widget child;
+
+  StateMarkerState createState() => new StateMarkerState();
+}
+
+class StateMarkerState extends State<StateMarker> {
+  String marker;
+
+  Widget build(BuildContext context) {
+    if (config.child != null)
+      return config.child;
+    return new Container();
+  }
+}
+
+void main() {
+  test('can reparent state', () {
+    testWidgets((WidgetTester tester) {
+      GlobalKey left = new GlobalKey();
+      GlobalKey right = new GlobalKey();
+
+      StateMarker grandchild = new StateMarker();
+      tester.pumpWidget(
+        new Stack([
+          new Container(
+            child: new StateMarker(key: left)
+          ),
+          new Container(
+            child: new StateMarker(
+              key: right,
+              child: grandchild
+            )
+          ),
+        ])
+      );
+
+      (left.currentState as StateMarkerState).marker = "left";
+      (right.currentState as StateMarkerState).marker = "right";
+
+      StateMarkerState grandchildState = tester.findStateByConfig(grandchild);
+      expect(grandchildState, isNotNull);
+      grandchildState.marker = "grandchild";
+
+      StateMarker newGrandchild = new StateMarker();
+      tester.pumpWidget(
+        new Stack([
+          new Container(
+            child: new StateMarker(
+              key: right,
+              child: newGrandchild
+            )
+          ),
+          new Container(
+            child: new StateMarker(key: left)
+          ),
+        ])
+      );
+
+      expect((left.currentState as StateMarkerState).marker, equals("left"));
+      expect((right.currentState as StateMarkerState).marker, equals("right"));
+
+      StateMarkerState newGrandchildState = tester.findStateByConfig(newGrandchild);
+      expect(newGrandchildState, isNotNull);
+      expect(newGrandchildState, equals(grandchildState));
+      expect(newGrandchildState.marker, equals("grandchild"));
+
+      tester.pumpWidget(
+        new Center(
+          child: new Container(
+            child: new StateMarker(
+              key: left,
+              child: new Container()
+            )
+          )
+        )
+      );
+
+      expect((left.currentState as StateMarkerState).marker, equals("left"));
+      expect(right.currentState, isNull);
+    });
+  });
+
+  test('can with scrollable list', () {
+    testWidgets((WidgetTester tester) {
+      GlobalKey key = new GlobalKey();
+
+      tester.pumpWidget(new StateMarker(key: key));
+
+      (key.currentState as StateMarkerState).marker = "marked";
+
+      tester.pumpWidget(new ScrollableList<int>(
+        items: [0],
+        itemExtent: 100.0,
+        itemBuilder: (BuildContext context, int item) {
+          return new Container(
+            key: new Key('container'),
+            height: 100.0,
+            child: new StateMarker(key: key)
+          );
+        }
+      ));
+
+      expect((key.currentState as StateMarkerState).marker, equals("marked"));
+
+      tester.pumpWidget(new StateMarker(key: key));
+
+      expect((key.currentState as StateMarkerState).marker, equals("marked"));
+    });
+  });
+}