flutter: minor improvements to the test

Remove 1 dock widget, added guest widget.
Testing if image diff works.

tests/flutter/integration_test/ui_test.dart

@@ -14,9 +14,11 @@ import 'dart:ui';
 
 import 'package:KDDockWidgets/KDDockWidgets.dart';
 import 'package:flutter/material.dart';
-import 'package:flutter/rendering.dart';
+import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:KDDockWidgets/widgets/DropAreaWidget.dart';
+import 'package:integration_test/integration_test.dart';
+import 'package:kddockwidgets_integration_tests/MyWidget.dart';
 
 import 'package:kddockwidgets_integration_tests/utils.dart';
 
@@ -67,19 +69,12 @@ class MyApp extends StatelessWidget {
 
 void main() async {
   testWidgets('Basic test', (WidgetTester tester) async {
-    final dock1 =
-        DockItem(uniqueName: "dw1", guestWidget: Container(color: Colors.cyan));
-    final dock2 =
-        DockItem(uniqueName: "dw2", guestWidget: Container(color: Colors.cyan));
-    final dock3 =
-        DockItem(uniqueName: "dw3", guestWidget: Container(color: Colors.cyan));
-
-    final dock11 = DockItem(
-        uniqueName: "dw11", guestWidget: Container(color: Colors.cyan));
-    final dock12 = DockItem(
-        uniqueName: "dw12", guestWidget: Container(color: Colors.cyan));
-    final dock13 = DockItem(
-        uniqueName: "dw13", guestWidget: Container(color: Colors.cyan));
+    final dock1 = DockItem(uniqueName: "dw1", guestWidget: MyWidget());
+    final dock2 = DockItem(uniqueName: "dw2", guestWidget: MyWidget());
+    final dock3 = DockItem(uniqueName: "dw3", guestWidget: MyWidget());
+
+    final dock11 = DockItem(uniqueName: "dw11", guestWidget: MyWidget());
+    final dock12 = DockItem(uniqueName: "dw12", guestWidget: MyWidget());
 
     final dropArea = DropArea();
     dropArea.addDockItem(dock1, Location.LocationOnTop);
@@ -88,7 +83,6 @@ void main() async {
     group.addDockWidget(dock3);
     group.addDockWidget(dock11);
     group.addDockWidget(dock12);
-    group.addDockWidget(dock13);
 
     dropArea.setLayoutSize(700, 700);
     final dropAreaWidget = DropAreaWidget(dropArea);

tests/flutter/lib/MyWidget.dart

@@ -0,0 +1,45 @@
+/*
+  This file is part of KDDockWidgets.
+
+  SPDX-FileCopyrightText: 2023 Klarälvdalens Datakonsult AB, a KDAB Group company <[email protected]>
+  Author: Sérgio Martins <[email protected]>
+
+  SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only
+
+  Contact KDAB at <[email protected]> for commercial licensing options.
+*/
+import 'dart:io';
+
+import 'package:flutter/material.dart';
+
+// ignore: must_be_immutable
+class MyWidget extends StatelessWidget {
+  static int nextImageId = 0;
+  final int imageId;
+  MyWidget({super.key}) : imageId = nextImageId {
+    MyWidget.nextImageId++;
+  }
+
+  String imageName() {
+    switch (imageId % 2) {
+      case 0:
+        return 'assets/KDAB_bubble_fulcolor.png';
+      case 1:
+        return 'assets/KDAB_bubble_blue.png';
+    }
+
+    return 'assets/KDAB_bubble_fulcolor.png';
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      color: Colors.white,
+      padding: const EdgeInsets.all(40.0),
+      child: Image.file(
+        File(imageName()),
+        fit: BoxFit.contain,
+      ),
+    );
+  }
+}