Add tests for material_state_mouse_cursor.0.dart API example. (#145987)

This PR contributes to https://github.com/flutter/flutter/issues/130459

### Description
- Updates `examples/api/lib/material/material_state/material_state_mouse_cursor.0.dart` to allow enable/disable `ListTile` in tests;
- Adds tests for `examples/api/lib/material/material_state/material_state_mouse_cursor.0.dart`.

dev/bots/check_code_samples.dart

@@ -313,7 +313,6 @@ final Set<String> _knownMissingTests = <String>{
   'examples/api/test/material/bottom_app_bar/bottom_app_bar.1_test.dart',
   'examples/api/test/material/theme/theme_extension.1_test.dart',
   'examples/api/test/material/material_state/material_state_border_side.0_test.dart',
-  'examples/api/test/material/material_state/material_state_mouse_cursor.0_test.dart',
   'examples/api/test/material/material_state/material_state_outlined_border.0_test.dart',
   'examples/api/test/material/material_state/material_state_property.0_test.dart',
   'examples/api/test/material/selectable_region/selectable_region.0_test.dart',

examples/api/lib/material/material_state/material_state_mouse_cursor.0.dart

@@ -17,7 +17,10 @@ class MaterialStateMouseCursorExampleApp extends StatelessWidget {
       home: Scaffold(
         appBar: AppBar(title: const Text('MaterialStateMouseCursor Sample')),
         body: const Center(
-          child: MaterialStateMouseCursorExample(),
+          child: MaterialStateMouseCursorExample(
+            // TRY THIS: Switch to get a different mouse cursor while hovering ListTile.
+            enabled: false,
+          ),
         ),
       ),
     );
@@ -40,14 +43,20 @@ class ListTileCursor extends MaterialStateMouseCursor {
 }
 
 class MaterialStateMouseCursorExample extends StatelessWidget {
-  const MaterialStateMouseCursorExample({super.key});
+  const MaterialStateMouseCursorExample({
+    required this.enabled,
+    super.key,
+  });
+
+  final bool enabled;
 
   @override
   Widget build(BuildContext context) {
-    return const ListTile(
+    return ListTile(
-      title: Text('Disabled ListTile'),
+      title: const Text('ListTile'),
-      enabled: false,
+      enabled: enabled,
-      mouseCursor: ListTileCursor(),
+      onTap: () {},
+      mouseCursor: const ListTileCursor(),
     );
   }
 }

examples/api/test/material/material_state/material_state_mouse_cursor.0_test.dart

@@ -0,0 +1,77 @@
+// Copyright 2014 The Flutter 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 'dart:ui';
+
+import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart';
+import 'package:flutter_api_samples/material/material_state/material_state_mouse_cursor.0.dart'
+    as example;
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets(
+    'MaterialStateMouseCursorExampleApp displays ListTile',
+    (WidgetTester tester) async {
+      await tester.pumpWidget(
+        const example.MaterialStateMouseCursorExampleApp(),
+      );
+
+      expect(find.byType(ListTile), findsOneWidget);
+      expect(find.text('ListTile'), findsOneWidget);
+    },
+  );
+
+  testWidgets(
+    'ListTile displays correct mouse cursor when enabled',
+    (WidgetTester tester) async {
+      await tester.pumpWidget(
+        const MaterialApp(
+          home: Scaffold(
+            body: example.MaterialStateMouseCursorExample(enabled: true),
+          ),
+        ),
+      );
+
+      final TestGesture gesture = await tester.createGesture(
+        kind: PointerDeviceKind.mouse,
+      );
+      await gesture.addPointer(
+        location: tester.getCenter(find.byType(ListTile)),
+      );
+      addTearDown(gesture.removePointer);
+
+      expect(
+        RendererBinding.instance.mouseTracker.debugDeviceActiveCursor(1),
+        SystemMouseCursors.click,
+      );
+    },
+  );
+
+  testWidgets(
+    'ListTile displays correct mouse cursor when disabled',
+    (WidgetTester tester) async {
+      await tester.pumpWidget(
+        const MaterialApp(
+          home: Scaffold(
+            body: example.MaterialStateMouseCursorExample(enabled: false),
+          ),
+        ),
+      );
+
+      final TestGesture gesture = await tester.createGesture(
+        kind: PointerDeviceKind.mouse,
+      );
+      await gesture.addPointer(
+        location: tester.getCenter(find.byType(ListTile)),
+      );
+      addTearDown(gesture.removePointer);
+
+      expect(
+        RendererBinding.instance.mouseTracker.debugDeviceActiveCursor(1),
+        SystemMouseCursors.forbidden,
+      );
+    },
+  );
+}