CXMM-10356 TestJira2Pr: Add dark mode to sample test app

lib/main.dart

@@ -19,21 +19,54 @@ void main() {
 ///
 /// Configure both keys in a local, gitignored `.env` file at the project
 /// root (see `.env.example`).
-class LocalyticsSampleApp extends StatelessWidget {
+ThemeData _appTheme(Brightness brightness) {
+  return ThemeData(
+    useMaterial3: true,
+    colorSchemeSeed: Colors.indigo,
+    brightness: brightness,
+  );
+}
+
+class LocalyticsSampleApp extends StatefulWidget {
   const LocalyticsSampleApp({super.key});
 
+  @override
+  State<LocalyticsSampleApp> createState() => _LocalyticsSampleAppState();
+}
+
+class _LocalyticsSampleAppState extends State<LocalyticsSampleApp> {
+  ThemeMode _themeMode = ThemeMode.light;
+
+  void _toggleThemeMode() {
+    setState(() {
+      _themeMode =
+          _themeMode == ThemeMode.light ? ThemeMode.dark : ThemeMode.light;
+    });
+  }
+
   @override
   Widget build(BuildContext context) {
     return MaterialApp(
       title: 'Localytics Flutter Sample',
-      theme: ThemeData(useMaterial3: true, colorSchemeSeed: Colors.indigo),
-      home: const _HomePage(),
+      theme: _appTheme(Brightness.light),
+      darkTheme: _appTheme(Brightness.dark),
+      themeMode: _themeMode,
+      home: _HomePage(
+        isDarkMode: _themeMode == ThemeMode.dark,
+        onToggleThemeMode: _toggleThemeMode,
+      ),
     );
   }
 }
 
 class _HomePage extends StatefulWidget {
-  const _HomePage();
+  const _HomePage({
+    required this.isDarkMode,
+    required this.onToggleThemeMode,
+  });
+
+  final bool isDarkMode;
+  final VoidCallback onToggleThemeMode;
 
   @override
   State<_HomePage> createState() => _HomePageState();
@@ -125,7 +158,20 @@ class _HomePageState extends State<_HomePage> {
   Widget build(BuildContext context) {
     final theme = Theme.of(context);
     return Scaffold(
-      appBar: AppBar(title: const Text('Localytics Flutter Sample')),
+      appBar: AppBar(
+        title: const Text('Localytics Flutter Sample'),
+        actions: <Widget>[
+          IconButton(
+            tooltip: widget.isDarkMode
+                ? 'Switch to light mode'
+                : 'Switch to dark mode',
+            onPressed: widget.onToggleThemeMode,
+            icon: Icon(
+              widget.isDarkMode ? Icons.light_mode : Icons.dark_mode,
+            ),
+          ),
+        ],
+      ),
       body: ListView(
         padding: const EdgeInsets.all(16),
         children: <Widget>[

test/widget_test.dart

@@ -10,6 +10,7 @@
 
 import 'dart:ui';
 
+import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 import 'package:localytics_flutter_tester/main.dart';
@@ -27,6 +28,7 @@ void main() {
 
     expect(find.text('Localytics Flutter Sample'), findsOneWidget);
     expect(find.text('Diagnostics'), findsOneWidget);
+    expect(find.byTooltip('Switch to dark mode'), findsOneWidget);
 
     for (final String section in <String>[
       'Privacy',
@@ -45,4 +47,32 @@ void main() {
       );
     }
   });
+
+  testWidgets('theme toggle switches between light and dark mode',
+      (WidgetTester tester) async {
+    await tester.pumpWidget(const LocalyticsSampleApp());
+    await tester.pumpAndSettle();
+
+    final Finder darkModeButton = find.byTooltip('Switch to dark mode');
+    expect(darkModeButton, findsOneWidget);
+
+    final MaterialApp materialAppBefore =
+        tester.widget<MaterialApp>(find.byType(MaterialApp));
+    expect(materialAppBefore.themeMode, ThemeMode.light);
+
+    await tester.tap(darkModeButton);
+    await tester.pumpAndSettle();
+
+    final MaterialApp materialAppAfter =
+        tester.widget<MaterialApp>(find.byType(MaterialApp));
+    expect(materialAppAfter.themeMode, ThemeMode.dark);
+    expect(find.byTooltip('Switch to light mode'), findsOneWidget);
+
+    await tester.tap(find.byTooltip('Switch to light mode'));
+    await tester.pumpAndSettle();
+
+    final MaterialApp materialAppRestored =
+        tester.widget<MaterialApp>(find.byType(MaterialApp));
+    expect(materialAppRestored.themeMode, ThemeMode.light);
+  });
 }