chore: moved timer logic to how to play dialog

lib/select_character/view/character_selection_page.dart

@@ -1,7 +1,5 @@
 // ignore_for_file: public_member_api_docs
 
-import 'dart:async';
-
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:pinball/l10n/l10n.dart';
@@ -48,34 +46,19 @@ class CharacterSelectionView extends StatelessWidget {
             const SizedBox(height: 20),
             TextButton(
               onPressed: () {
-                late Timer timer;
                 // TODO(arturplaczek): remove after merge StarBlocListener
                 final height = MediaQuery.of(context).size.height * 0.5;
 
                 Navigator.of(context).pop();
                 showDialog<void>(
                   context: context,
-                  builder: (context) {
-                    timer = Timer(
-                      const Duration(seconds: 3),
-                      () {
-                        Navigator.of(context).pop();
-                      },
-                    );
-                    return Center(
+                  builder: (context) => Center(
                     child: SizedBox(
                       height: height,
                       width: height * 1.4,
                       child: const HowToPlayDialog(),
                     ),
-                    );
-                  },
-                ).then(
-                  (_) {
-                    if (timer.isActive) {
-                      timer.cancel();
-                    }
-                  },
+                  ),
                 );
               },
               child: Text(l10n.start),

lib/start_game/widgets/how_to_play_dialog.dart

@@ -1,5 +1,7 @@
 // ignore_for_file: public_member_api_docs
 
+import 'dart:async';
+
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:pinball/gen/gen.dart';
@@ -49,9 +51,31 @@ extension on Control {
   }
 }
 
-class HowToPlayDialog extends StatelessWidget {
+class HowToPlayDialog extends StatefulWidget {
   const HowToPlayDialog({Key? key}) : super(key: key);
 
+  @override
+  State<HowToPlayDialog> createState() => _HowToPlayDialogState();
+}
+
+class _HowToPlayDialogState extends State<HowToPlayDialog> {
+  late Timer closeTimer;
+  @override
+  void initState() {
+    super.initState();
+    closeTimer = Timer(const Duration(seconds: 3), () {
+      if (mounted) {
+        Navigator.of(context).maybePop();
+      }
+    });
+  }
+
+  @override
+  void dispose() {
+    closeTimer.cancel();
+    super.dispose();
+  }
+
   @override
   Widget build(BuildContext context) {
     final isMobile = defaultTargetPlatform == TargetPlatform.iOS ||

test/select_character/view/character_selection_page_test.dart

@@ -91,9 +91,23 @@ void main() {
         'is displayed for 3 seconds when start is tapped',
         (tester) async {
           await tester.pumpApp(
-            CharacterSelectionView(),
+            Scaffold(
+              body: Builder(
+                builder: (context) {
+                  return ElevatedButton(
+                    onPressed: () {
+                      Navigator.of(context)
+                          .push<void>(CharacterSelectionDialog.route());
+                    },
+                    child: Text('Tap me'),
+                  );
+                },
+              ),
+            ),
             characterThemeCubit: characterThemeCubit,
           );
+          await tester.tap(find.text('Tap me'));
+          await tester.pumpAndSettle();
           await tester.ensureVisible(find.byType(TextButton));
           await tester.tap(find.byType(TextButton));
           await tester.pumpAndSettle();