feat: add setMocks method for use in testing (g123k#73)

Author: riscait

lib/flutter_app_badger.dart

@@ -1,21 +1,62 @@
 import 'dart:async';
 
+import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 
 class FlutterAppBadger {
   static const MethodChannel _channel =
       const MethodChannel('g123k/flutter_app_badger');
 
-  static Future<void> updateBadgeCount(int count) {
+  static Future<void> updateBadgeCount(int count) async {
+    final mock = _mockUpdateBadgeCount;
+    if (mock != null) {
+      await mock(count);
+      return;
+    }
+
     return _channel.invokeMethod('updateBadgeCount', {"count": count});
   }
 
-  static Future<void> removeBadge() {
+  static Future<void> removeBadge() async {
+    final mock = _mockRemoveBadge;
+    if (mock != null) {
+      await mock();
+      return;
+    }
+
     return _channel.invokeMethod('removeBadge');
   }
 
   static Future<bool> isAppBadgeSupported() async {
-    bool? appBadgeSupported = await _channel.invokeMethod('isAppBadgeSupported');
+    final mock = _mockIsAppBadgeSupported;
+    if (mock != null) {
+      return mock();
+    }
+
+    bool? appBadgeSupported =
+        await _channel.invokeMethod('isAppBadgeSupported');
     return appBadgeSupported ?? false;
   }
+
+  static Future<void> Function(int count)? _mockUpdateBadgeCount;
+  static Future<void> Function()? _mockRemoveBadge;
+  static Future<bool> Function()? _mockIsAppBadgeSupported;
+
+  @visibleForTesting
+  static void setMocks({
+    Future<void> Function(int count)? updateBadgeCount,
+    Future<void> Function()? removeBadge,
+    Future<bool> Function()? isAppBadgeSupported,
+  }) {
+    _mockUpdateBadgeCount = updateBadgeCount;
+    _mockRemoveBadge = removeBadge;
+    _mockIsAppBadgeSupported = isAppBadgeSupported;
+  }
+
+  @visibleForTesting
+  static void clearMocks() {
+    _mockUpdateBadgeCount = null;
+    _mockRemoveBadge = null;
+    _mockIsAppBadgeSupported = null;
+  }
 }