fix: test using matcher

Author: cybex-dev

pubspec.yaml

@@ -29,6 +29,7 @@ dev_dependencies:
   flutter_lints: ^2.0.2
   flutter_test:
     sdk: flutter
+  matcher: ^0.12.17
 
 # For information on the generic Dart part of this file, see the
 # following page: https://dart.dev/tools/pub/pubspec

test/twilio_voice_test.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:matcher/matcher.dart' as matcher;
 
 void main() {
   const MethodChannel channel = MethodChannel('twilio_voice');
@@ -14,6 +15,7 @@ void main() {
   });
 
   test("Mock Test", () async {
-    expect(await channel.invokeMethod("42"), equals("42"));
+    final result = await channel.invokeMethod("42");
+    expect(result, matcher.equals("42"));
   });
 }