tests and mocks for e2e testing (#78)

* tests and mocks for e2e testing

* formatting

* fix analyze errors

lib/src/support/native.dart

@@ -36,5 +36,6 @@ class Native {
     } catch (error) {
       logger.warning('appleOSVersionString did throw error: ${error}');
     }
+    return null;
   }
 }

lib/src/support/platform.dart

@@ -1,9 +1,17 @@
+import 'dart:io';
+
+import 'package:meta/meta.dart';
+
 import 'platform/io.dart' if (dart.library.html) 'platform/web.dart';
 
 // Returns the current platform which works for both web and devices.
 PlatformType lkPlatform() => lkPlatformImplementation();
+
 bool lkPlatformIs(PlatformType type) => lkPlatform() == type;
 
+@internal
+bool lkPlatformIsTest() => Platform.environment.containsKey('FLUTTER_TEST');
+
 enum PlatformType {
   web,
   windows,

lib/src/support/websocket.dart

@@ -23,6 +23,7 @@ class WebSocketEventHandlers {
   final WebSocketOnData? onData;
   final WebSocketOnError? onError;
   final WebSocketOnDispose? onDispose;
+
   const WebSocketEventHandlers({
     this.onData,
     this.onError,
@@ -30,12 +31,13 @@ class WebSocketEventHandlers {
   });
 }
 
+typedef WebSocketConnector = Future<LiveKitWebSocket> Function(Uri uri,
+    [WebSocketEventHandlers? options]);
+
 abstract class LiveKitWebSocket extends Disposable {
   void send(List<int> data);
 
-  static Future<LiveKitWebSocket> connect(
-    Uri uri, [
-    WebSocketEventHandlers? options,
-  ]) =>
+  static Future<LiveKitWebSocket> connect(Uri uri,
+          [WebSocketEventHandlers? options]) =>
       lkWebSocketConnect(uri, options);
 }