feat: add parameter to configuration to supply an implementation of the killswitch service

lib/src/models/start_configuration.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_introduction/flutter_introduction.dart';
+import 'package:flutter_start/src/services/killswitch_service.dart';
 
 /// An immutable class that represents the configuration for
 /// starting a user story.
@@ -22,6 +23,7 @@ class StartUserStoryConfiguration {
     this.splashScreenCenterWidget,
     this.splashScreenBackgroundColor,
     this.canPopFromIntroduction = true,
+    this.killswitchService,
   });
 
   /// You can use this to build your own splash screen.
@@ -45,6 +47,7 @@ class StartUserStoryConfiguration {
       introductionOptionsBuilder;
   final Widget? introductionFallbackScreen;
   final IntroductionService? introductionService;
+  final KillswitchService? killswitchService;
   final ScrollPhysics? introductionScrollPhysics;
 
   /// If the introduction should be shown.

lib/src/services/killswitch_service.dart

@@ -4,7 +4,7 @@ import 'package:http/http.dart' as http;
 import 'package:package_info_plus/package_info_plus.dart';
 
 /// A service class to check if a killswitch is active for the current app.
-class KillswitchService {
+abstract interface class KillswitchService {
   /// Checks if the killswitch is active for the current app.
   ///
   /// It makes a GET request to a specific URL with the app
@@ -14,6 +14,11 @@ class KillswitchService {
   ///
   /// Returns a [Future] that completes with 'true' if the killswitch is active,
   /// and 'false' otherwise.
+  Future<bool> isKillswitchActive() => throw UnimplementedError();
+}
+
+class DefaultKillswitchService implements KillswitchService {
+  @override
   Future<bool> isKillswitchActive() async {
     var packageInfo = await PackageInfo.fromPlatform();
     var appName = packageInfo.appName;

lib/src/user_stories/flutter_start_userstory_go_router.dart

@@ -31,9 +31,14 @@ List<GoRoute> getStartStoryRoutes(
                 Future.delayed(
                   Duration.zero,
                   () async {
-                    if (configuration.useKillswitch)
+                    if (configuration.useKillswitch) {
+                      var killswitchService = configuration.killswitchService ??
+                          DefaultKillswitchService();
+
                       isAllowedToPassThrough =
-                          await KillswitchService().isKillswitchActive();
+                          await killswitchService.isKillswitchActive();
+                    }
+
                     var introService = configuration.introductionService ??
                         IntroductionService(
                           SharedPreferencesIntroductionDataProvider(),

lib/src/user_stories/flutter_start_userstory_navigator.dart

@@ -28,9 +28,14 @@ Widget _splashScreen(
         Future.delayed(
           Duration.zero,
           () async {
-            if (configuration.useKillswitch)
+            if (configuration.useKillswitch) {
+              var killswitchService =
+                  configuration.killswitchService ?? DefaultKillswitchService();
+
               isAllowedToPassThrough =
-                  await KillswitchService().isKillswitchActive();
+                  await killswitchService.isKillswitchActive();
+            }
+
             var introService = configuration.introductionService ??
                 IntroductionService(
                   SharedPreferencesIntroductionDataProvider(),