FlutterDriver: Flutter驱动程序扩展需要很长时间才能可用

Question

我正在尝试按照网页上提供的指令运行flutter集成测试：https://flutter.dev/docs/cookbook/testing/integration/introduction，但当尝试使用iOS设备执行时，它总是失败并出现flutterdriver超时，但如果我使用安卓设备执行相同的代码，它会运行成功。

执行的命令是：

flutter driver --target=test_driver/app.dart

和(仅在iOS中)，显示的错误如下：

...
flutter: Observatory listening on http://127.0.0.1:49605/Jh_J7boSKBk=/  
Installing and launching...                                        22.5s
[info ] FlutterDriver: Connecting to Flutter application at http://127.0.0.1:1043/Jh_J7boSKBk=/
[trace] FlutterDriver: Isolate found with number: 589047572
[trace] FlutterDriver: Isolate is paused at start.
[trace] FlutterDriver: Attempting to resume isolate
[trace] FlutterDriver: Waiting for service extension
flutter: main dev
[warning] FlutterDriver: Flutter Driver extension is taking a long time to become available. Ensure your test app (often "lib/main.dart") imports "package:flutter_driver/driver_extension.dart" and calls enableFlutterDriverExtension() as the first call in main().

看起来，当它在iOS中执行时，它完全忽略了指定的目标，并试图直接运行lib/main.dart文件，但是，为什么呢？

以下网页说明的意思是使用两个文件进行测试: test_driver/app.dart和test_driver/app_test.dart

test_driver/app.dart

import 'package:flutter_driver/driver_extension.dart';
import 'package:my_app/main.dart' as app;

void main() async {
  // This line enables the extension
  await enableFlutterDriverExtension();

  // Call the `main()` function of your app or call `runApp` with any widget you
  // are interested in testing.
  await app.main();
}

test_driver/app_test.dart

import 'package:flutter_driver/flutter_driver.dart';
import 'package:test/test.dart';

void main() {
  group('end-to-end test', () {
    FlutterDriver driver;

    setUpAll(() async {
      // Connect to a running Flutter application instance.
      driver = await FlutterDriver.connect();
    });

    tearDownAll(() async {
      if (driver != null)
        driver.close();
    });

    test('whatever', () async {
       //whatever
    });
  });
}

正如这里所评论的：#17184，在main.dart中引入enableFlutterDriverExtension()可以修复它，但我不希望在应用程序代码中编写任何额外的东西。

有没有可能使用另一种方法来修复它？

谢谢

Answer 1

我遵循了docs for writing integration tests上的步骤，它在Flutter稳定(1.22.5版)和master(1.26.0-2.0.pre.281版)通道上都工作得很好。虽然docs中的命令演示了flutter drive的用法，但在我的测试中，使用flutter driver似乎也运行得很好。

抛开这个问题不谈，即使我不能在本地复制这个问题，这个问题似乎已经通过遵循GitHub issue thread中提到的解决方法来解决了。