flutter_flutter/packages/flutter/test/widget/stack_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:flutter_test/flutter_test.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/widgets.dart';

import '../rendering/rendering_tester.dart';

class TestPaintingContext implements PaintingContext {
  final List<Invocation> invocations = <Invocation>[];

  @override
    void noSuchMethod(Invocation invocation) {
      invocations.add(invocation);
    }
}

void main() {
  testWidgets('Can construct an empty Stack', (WidgetTester tester) async {
    await tester.pumpWidget(new Stack());
  });

  testWidgets('Can construct an empty Centered Stack', (WidgetTester tester) async {
    await tester.pumpWidget(new Center(child: new Stack()));
  });

  testWidgets('Can change position data', (WidgetTester tester) async {
    Key key = new Key('container');

    await tester.pumpWidget(
      new Stack(
        children: <Widget>[
          new Positioned(
            left: 10.0,
            child: new Container(
              key: key,
              width: 10.0,
              height: 10.0
            )
          )
        ]
      )
    );

    Element container;
    StackParentData parentData;

    container = tester.element(find.byKey(key));
    parentData = container.renderObject.parentData;
    expect(parentData.top, isNull);
    expect(parentData.right, isNull);
    expect(parentData.bottom, isNull);
    expect(parentData.left, equals(10.0));
    expect(parentData.width, isNull);
    expect(parentData.height, isNull);

    await tester.pumpWidget(
      new Stack(
        children: <Widget>[
          new Positioned(
            right: 10.0,
            child: new Container(
              key: key,
              width: 10.0,
              height: 10.0
            )
          )
        ]
      )
    );

    container = tester.element(find.byKey(key));
    parentData = container.renderObject.parentData;
    expect(parentData.top, isNull);
    expect(parentData.right, equals(10.0));
    expect(parentData.bottom, isNull);
    expect(parentData.left, isNull);
    expect(parentData.width, isNull);
    expect(parentData.height, isNull);
  });

  testWidgets('Can remove parent data', (WidgetTester tester) async {
    Key key = new Key('container');
    Container container = new Container(key: key, width: 10.0, height: 10.0);

    await tester.pumpWidget(new Stack(children: <Widget>[ new Positioned(left: 10.0, child: container) ]));
    Element containerElement = tester.element(find.byKey(key));

    StackParentData parentData;
    parentData = containerElement.renderObject.parentData;
    expect(parentData.top, isNull);
    expect(parentData.right, isNull);
    expect(parentData.bottom, isNull);
    expect(parentData.left, equals(10.0));
    expect(parentData.width, isNull);
    expect(parentData.height, isNull);

    await tester.pumpWidget(new Stack(children: <Widget>[ container ]));
    containerElement = tester.element(find.byKey(key));

    parentData = containerElement.renderObject.parentData;
    expect(parentData.top, isNull);
    expect(parentData.right, isNull);
    expect(parentData.bottom, isNull);
    expect(parentData.left, isNull);
    expect(parentData.width, isNull);
    expect(parentData.height, isNull);
  });

  testWidgets('Can align non-positioned children', (WidgetTester tester) async {
    Key child0Key = new Key('child0');
    Key child1Key = new Key('child1');

    await tester.pumpWidget(
      new Center(
        child: new Stack(
          children: <Widget>[
            new Container(key: child0Key, width: 20.0, height: 20.0),
            new Container(key: child1Key, width: 10.0, height: 10.0)
          ],
          alignment: const FractionalOffset(0.5, 0.5)
        )
      )
    );

    Element child0 = tester.element(find.byKey(child0Key));
    final StackParentData child0RenderObjectParentData = child0.renderObject.parentData;
    expect(child0RenderObjectParentData.offset, equals(const Offset(0.0, 0.0)));

    Element child1 = tester.element(find.byKey(child1Key));
    final StackParentData child1RenderObjectParentData = child1.renderObject.parentData;
    expect(child1RenderObjectParentData.offset, equals(const Offset(5.0, 5.0)));
  });

  testWidgets('Can construct an empty IndexedStack', (WidgetTester tester) async {
    await tester.pumpWidget(new IndexedStack());
  });

  testWidgets('Can construct an empty Centered IndexedStack', (WidgetTester tester) async {
    await tester.pumpWidget(new Center(child: new IndexedStack()));
  });

  testWidgets('Can construct an IndexedStack', (WidgetTester tester) async {
    int itemCount = 3;
    List<int> itemsPainted;

    Widget buildFrame(int index) {
      itemsPainted = <int>[];
      List<Widget> items = new List<Widget>.generate(itemCount, (int i) {
        return new CustomPaint(
          child: new Text('$i'),
          painter: new TestCallbackPainter(
            onPaint: () { itemsPainted.add(i); }
          )
        );
      });
      return new Center(child: new IndexedStack(children: items, index: index));
    }

    await tester.pumpWidget(buildFrame(0));
    expect(find.text('0'), findsOneWidget);
    expect(find.text('1'), findsOneWidget);
    expect(find.text('2'), findsOneWidget);
    expect(itemsPainted, equals(<int>[0]));

    await tester.pumpWidget(buildFrame(1));
    expect(itemsPainted, equals(<int>[1]));

    await tester.pumpWidget(buildFrame(2));
    expect(itemsPainted, equals(<int>[2]));
  });

  testWidgets('Can hit test an IndexedStack', (WidgetTester tester) async {
    Key key = new Key('indexedStack');
    int itemCount = 3;
    List<int> itemsTapped;

    Widget buildFrame(int index) {
      itemsTapped = <int>[];
      List<Widget> items = new List<Widget>.generate(itemCount, (int i) {
        return new GestureDetector(child: new Text('$i'), onTap: () { itemsTapped.add(i); });
      });
      return new Center(child: new IndexedStack(children: items, key: key, index: index));
    }

    await tester.pumpWidget(buildFrame(0));
    expect(itemsTapped, isEmpty);
    await tester.tap(find.byKey(key));
    expect(itemsTapped, <int>[0]);

    await tester.pumpWidget(buildFrame(2));
    expect(itemsTapped, isEmpty);
    await tester.tap(find.byKey(key));
    expect(itemsTapped, <int>[2]);
  });

  testWidgets('Can set width and height', (WidgetTester tester) async {
    Key key = new Key('container');

    BoxDecoration kBoxDecoration = new BoxDecoration(
      backgroundColor: new Color(0xFF00FF00)
    );

    await tester.pumpWidget(
      new Stack(
        children: <Widget>[
          new Positioned(
            left: 10.0,
            width: 11.0,
            height: 12.0,
            child: new DecoratedBox(key: key, decoration: kBoxDecoration)
          )
        ]
      )
    );

    Element box;
    RenderBox renderBox;
    StackParentData parentData;

    box = tester.element(find.byKey(key));
    renderBox = box.renderObject;
    parentData = renderBox.parentData;
    expect(parentData.top, isNull);
    expect(parentData.right, isNull);
    expect(parentData.bottom, isNull);
    expect(parentData.left, equals(10.0));
    expect(parentData.width, equals(11.0));
    expect(parentData.height, equals(12.0));
    expect(parentData.offset.dx, equals(10.0));
    expect(parentData.offset.dy, equals(0.0));
    expect(renderBox.size.width, equals(11.0));
    expect(renderBox.size.height, equals(12.0));

    await tester.pumpWidget(
      new Stack(
        children: <Widget>[
          new Positioned(
            right: 10.0,
            width: 11.0,
            height: 12.0,
            child: new DecoratedBox(key: key, decoration: kBoxDecoration)
          )
        ]
      )
    );

    box = tester.element(find.byKey(key));
    renderBox = box.renderObject;
    parentData = renderBox.parentData;
    expect(parentData.top, isNull);
    expect(parentData.right, equals(10.0));
    expect(parentData.bottom, isNull);
    expect(parentData.left, isNull);
    expect(parentData.width, equals(11.0));
    expect(parentData.height, equals(12.0));
    expect(parentData.offset.dx, equals(779.0));
    expect(parentData.offset.dy, equals(0.0));
    expect(renderBox.size.width, equals(11.0));
    expect(renderBox.size.height, equals(12.0));
  });

  testWidgets('Stack clip test', (WidgetTester tester) async {
    await tester.pumpWidget(
      new Center(
        child: new Stack(
          children: <Widget>[
            new Container(
              width: 100.0,
              height: 100.0
            ),
            new Positioned(
              top: 0.0,
              left: 0.0,
              child: new Container(
                width: 200.0,
                height: 200.0
              )
            )
          ]
        )
      )
    );

    RenderBox box = tester.renderObject(find.byType(Stack));
    TestPaintingContext context = new TestPaintingContext();
    box.paint(context, Offset.zero);
    expect(context.invocations.first.memberName, equals(#pushClipRect));

    await tester.pumpWidget(
      new Center(
        child: new Stack(
          overflow: Overflow.visible,
          children: <Widget>[
            new Container(
              width: 100.0,
              height: 100.0
            ),
            new Positioned(
              top: 0.0,
              left: 0.0,
              child: new Container(
                width: 200.0,
                height: 200.0
              )
            )
          ]
        )
      )
    );

    box = tester.renderObject(find.byType(Stack));
    context = new TestPaintingContext();
    box.paint(context, Offset.zero);
    expect(context.invocations.first.memberName, equals(#paintChild));
  });
}