Add tests for ParentData

packages/flutter/lib/src/fn3/binding.dart

@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:sky' as sky;
 import 'package:sky/animation.dart';
 import 'package:sky/rendering.dart';
 import 'package:sky/src/fn3/framework.dart';
@@ -156,8 +155,12 @@ class RenderObjectToWidgetElement<T extends RenderObject> extends RenderObjectEl
     renderObject.child = child;
   }
 
+  void moveChildRenderObject(RenderObject child, dynamic slot) {
+    assert(false);
+  }
+
   void removeChildRenderObject(RenderObject child) {
     assert(renderObject.child == child);
     renderObject.child = null;
   }
-}
+}

packages/flutter/lib/src/fn3/framework.dart

@@ -361,6 +361,8 @@ abstract class ParentDataWidget extends ProxyWidget {
   ParentDataWidget({ Key key, Widget child })
     : super(key: key, child: child);
 
+  ParentDataElement createElement() => new ParentDataElement(this);
+
   /// Subclasses should override this function to ensure that they are placed
   /// inside widgets that expect them.
   ///
@@ -600,6 +602,11 @@ abstract class Element<T extends Widget> implements BuildContext {
 typedef Widget WidgetBuilder(BuildContext context);
 typedef void BuildScheduler(BuildableElement element);
 
+class ErrorWidget extends LeafRenderObjectWidget {
+  RenderBox createRenderObject() => new RenderErrorBox();
+  void updateRenderObject(RenderObject renderObject, RenderObjectWidget oldWidget) { }
+}
+
 /// Base class for the instantiation of StatelessComponent and StatefulComponent
 /// widgets.
 abstract class BuildableElement<T extends Widget> extends Element<T> {
@@ -637,8 +644,17 @@ abstract class BuildableElement<T extends Widget> extends Element<T> {
       assert(built != null);
     } catch (e, stack) {
       _debugReportException('building $this', e, stack);
+      built = new ErrorWidget();
+    }
+
+    try {
+      _child = updateChild(_child, built, _slot);
+      assert(_child != null);
+    } catch (e, stack) {
+      _debugReportException('building $this', e, stack);
+      built = new ErrorWidget();
+      _child = updateChild(null, built, _slot);
     }
-    _child = updateChild(_child, built, _slot);
   }
 
   static BuildScheduler scheduleBuildFor;
@@ -721,6 +737,23 @@ class StatefulComponentElement extends BuildableElement<StatefulComponent> {
 class ParentDataElement extends StatelessComponentElement<ParentDataWidget> {
   ParentDataElement(ParentDataWidget widget) : super(widget);
 
+  void mount(Element parent, dynamic slot) {
+    assert(() {
+      Element ancestor = parent;
+      while (ancestor is! RenderObjectElement) {
+        assert(ancestor != null);
+        assert(() {
+          'You cannot nest parent data widgets inside one another.';
+          return ancestor is! ParentDataElement;
+        });
+        ancestor = ancestor._parent;
+      }
+      _widget.debugValidateAncestor(ancestor._widget);
+      return true;
+    });
+    super.mount(parent, slot);
+  }
+
   void update(ParentDataWidget newWidget) {
     ParentDataWidget oldWidget = widget;
     super.update(newWidget);
@@ -813,10 +846,6 @@ abstract class RenderObjectElement<T extends RenderObjectWidget> extends Element
   }
 
   void updateParentData(ParentDataWidget parentData) {
-    assert(() {
-      parentData.debugValidateAncestor(_ancestorRenderObjectElement.widget);
-      return true;
-    });
     parentData.applyParentData(renderObject);
   }
 
@@ -1125,12 +1154,14 @@ typedef void WidgetsExceptionHandler(String context, dynamic exception, StackTra
 /// [debugDumpApp()].
 WidgetsExceptionHandler debugWidgetsExceptionHandler;
 void _debugReportException(String context, dynamic exception, StackTrace stack) {
-  print('------------------------------------------------------------------------');
-  'Exception caught while $context'.split('\n').forEach(print);
-  print('$exception');
-  print('Stack trace:');
-  '$stack'.split('\n').forEach(print);
-  if (debugWidgetsExceptionHandler != null)
+  if (debugWidgetsExceptionHandler != null) {
     debugWidgetsExceptionHandler(context, exception, stack);
-  print('------------------------------------------------------------------------');
+  } else {
+    print('------------------------------------------------------------------------');
+    'Exception caught while $context'.split('\n').forEach(print);
+    print('$exception');
+    print('Stack trace:');
+    '$stack'.split('\n').forEach(print);
+    print('------------------------------------------------------------------------');
+  }
 }

packages/unit/test/fn3/parent_data_test.dart

@@ -0,0 +1,287 @@
+import 'package:sky/rendering.dart';
+import 'package:sky/src/fn3.dart';
+import 'package:test/test.dart';
+
+import 'test_widgets.dart';
+import 'widget_tester.dart';
+
+class TestParentData {
+  TestParentData({ this.top, this.right, this.bottom, this.left });
+
+  final double top;
+  final double right;
+  final double bottom;
+  final double left;
+}
+
+void checkTree(WidgetTester tester, List<TestParentData> expectedParentData) {
+  MultiChildRenderObjectElement element =
+      tester.findElement((element) => element is MultiChildRenderObjectElement);
+  expect(element, isNotNull);
+  expect(element.renderObject is RenderStack, isTrue);
+  RenderStack renderObject = element.renderObject;
+  try {
+    RenderObject child = renderObject.firstChild;
+    for (TestParentData expected in expectedParentData) {
+      expect(child is RenderDecoratedBox, isTrue);
+      RenderDecoratedBox decoratedBox = child;
+      expect(decoratedBox.parentData is StackParentData, isTrue);
+      StackParentData parentData = decoratedBox.parentData;
+      expect(parentData.top, equals(expected.top));
+      expect(parentData.right, equals(expected.right));
+      expect(parentData.bottom, equals(expected.bottom));
+      expect(parentData.left, equals(expected.left));
+      child = decoratedBox.parentData.nextSibling;
+    }
+    expect(child, isNull);
+  } catch (e) {
+    print(renderObject.toStringDeep());
+    rethrow;
+  }
+}
+
+final TestParentData kNonPositioned = new TestParentData();
+
+void main() {
+  dynamic cachedException;
+
+  setUp(() {
+    assert(cachedException == null);
+    debugWidgetsExceptionHandler = (String context, dynamic exception, StackTrace stack) {
+      cachedException = exception;
+    };
+  });
+
+  tearDown(() {
+    cachedException = null;
+    debugWidgetsExceptionHandler = null;
+  });
+
+  test('ParentDataWidget control test', () {
+    WidgetTester tester = new WidgetTester();
+
+    tester.pumpFrame(
+      new Stack([
+        new DecoratedBox(decoration: kBoxDecorationA),
+        new Positioned(
+          top: 10.0,
+          left: 10.0,
+          child: new DecoratedBox(decoration: kBoxDecorationB)
+        ),
+        new DecoratedBox(decoration: kBoxDecorationC),
+      ])
+    );
+
+    checkTree(tester, [
+      kNonPositioned,
+      new TestParentData(top: 10.0, left: 10.0),
+      kNonPositioned,
+    ]);
+
+    tester.pumpFrame(
+      new Stack([
+        new Positioned(
+          bottom: 5.0,
+          right: 7.0,
+          child: new DecoratedBox(decoration: kBoxDecorationA)
+        ),
+        new Positioned(
+          top: 10.0,
+          left: 10.0,
+          child: new DecoratedBox(decoration: kBoxDecorationB)
+        ),
+        new DecoratedBox(decoration: kBoxDecorationC),
+      ])
+    );
+
+    checkTree(tester, [
+      new TestParentData(bottom: 5.0, right: 7.0),
+      new TestParentData(top: 10.0, left: 10.0),
+      kNonPositioned,
+    ]);
+
+    DecoratedBox kDecoratedBoxA = new DecoratedBox(decoration: kBoxDecorationA);
+    DecoratedBox kDecoratedBoxB = new DecoratedBox(decoration: kBoxDecorationB);
+    DecoratedBox kDecoratedBoxC = new DecoratedBox(decoration: kBoxDecorationC);
+
+    tester.pumpFrame(
+      new Stack([
+        new Positioned(
+          bottom: 5.0,
+          right: 7.0,
+          child: kDecoratedBoxA
+        ),
+        new Positioned(
+          top: 10.0,
+          left: 10.0,
+          child: kDecoratedBoxB
+        ),
+        kDecoratedBoxC,
+      ])
+    );
+
+    checkTree(tester, [
+      new TestParentData(bottom: 5.0, right: 7.0),
+      new TestParentData(top: 10.0, left: 10.0),
+      kNonPositioned,
+    ]);
+
+    tester.pumpFrame(
+      new Stack([
+        new Positioned(
+          bottom: 6.0,
+          right: 8.0,
+          child: kDecoratedBoxA
+        ),
+        new Positioned(
+          left: 10.0,
+          right: 10.0,
+          child: kDecoratedBoxB
+        ),
+        kDecoratedBoxC,
+      ])
+    );
+
+    checkTree(tester, [
+      new TestParentData(bottom: 6.0, right: 8.0),
+      new TestParentData(left: 10.0, right: 10.0),
+      kNonPositioned,
+    ]);
+
+    tester.pumpFrame(
+      new Stack([
+        kDecoratedBoxA,
+        new Positioned(
+          left: 11.0,
+          right: 12.0,
+          child: new Container(child: kDecoratedBoxB)
+        ),
+        kDecoratedBoxC,
+      ])
+    );
+
+    checkTree(tester, [
+      kNonPositioned,
+      new TestParentData(left: 11.0, right: 12.0),
+      kNonPositioned,
+    ]);
+
+    tester.pumpFrame(
+      new Stack([
+        kDecoratedBoxA,
+        new Positioned(
+          right: 10.0,
+          child: new Container(child: kDecoratedBoxB)
+        ),
+        new Container(
+          child: new Positioned(
+            top: 8.0,
+            child: kDecoratedBoxC
+          )
+        )
+      ])
+    );
+
+    checkTree(tester, [
+      kNonPositioned,
+      new TestParentData(right: 10.0),
+      new TestParentData(top: 8.0),
+    ]);
+
+    tester.pumpFrame(
+      new Stack([
+        new Positioned(
+          right: 10.0,
+          child: new FlipComponent(left: kDecoratedBoxA, right: kDecoratedBoxB)
+        ),
+      ])
+    );
+
+    checkTree(tester, [
+      new TestParentData(right: 10.0),
+    ]);
+
+    flipStatefulComponent(tester);
+    tester.pumpFrameWithoutChange();
+
+    checkTree(tester, [
+      new TestParentData(right: 10.0),
+    ]);
+
+    tester.pumpFrame(
+      new Stack([
+        new Positioned(
+          top: 7.0,
+          child: new FlipComponent(left: kDecoratedBoxA, right: kDecoratedBoxB)
+        ),
+      ])
+    );
+
+    checkTree(tester, [
+      new TestParentData(top: 7.0),
+    ]);
+
+    flipStatefulComponent(tester);
+    tester.pumpFrameWithoutChange();
+
+    checkTree(tester, [
+      new TestParentData(top: 7.0),
+    ]);
+
+    tester.pumpFrame(
+      new Stack([])
+    );
+
+    checkTree(tester, []);
+  });
+
+  test('ParentDataWidget conflicting data', () {
+    WidgetTester tester = new WidgetTester();
+
+    expect(cachedException, isNull);
+
+    tester.pumpFrame(
+      new Stack([
+        new Positioned(
+          top: 5.0,
+          bottom: 8.0,
+          child: new Positioned(
+            top: 6.0,
+            left: 7.0,
+            child: new DecoratedBox(decoration: kBoxDecorationB)
+          )
+        )
+      ])
+    );
+
+    expect(cachedException, isNotNull);
+    cachedException = null;
+
+    tester.pumpFrame(new Stack([]));
+
+    checkTree(tester, []);
+    expect(cachedException, isNull);
+
+    tester.pumpFrame(
+      new Container(
+        child: new Flex([
+          new Positioned(
+            top: 6.0,
+            left: 7.0,
+            child: new DecoratedBox(decoration: kBoxDecorationB)
+          )
+        ])
+      )
+    );
+
+    expect(cachedException, isNotNull);
+    cachedException = null;
+
+    tester.pumpFrame(
+      new Stack([])
+    );
+
+    checkTree(tester, []);
+  });
+
+}