Exception: DriverError: Error in Flutter application: Uncaught extension error while executing tap: Guarded function conflict

Question

I am trying to run an automated test on a flutter application, but the error below is generated when the application is waiting for a home page to load

VMServiceFlutterDriver: waitFor message is taking a long time to complete...
VMServiceFlutterDriver: waitFor message is taking a long time to complete...
VMServiceFlutterDriver: tap message is taking a long time to complete...
VMServiceFlutterDriver: waitFor message is taking a long time to complete...
VMServiceFlutterDriver: waitFor message is taking a long time to complete...
VMServiceFlutterDriver: tap message is taking a long time to complete...
VMServiceFlutterDriver: waitFor message is taking a long time to complete...
Exception: DriverError: Error in Flutter application: Uncaught extension error while executing tap: Guarded function conflict.
You must use "await" with all Future-returning test APIs.
The guarded method "tapAt" from class WidgetController was called from package:flutter_driver/src/extension/extension.dart on line 460.
Then, the "_getElementPoint" method (also from class WidgetController) was called again from package:flutter_driver/src/extension/extension.dart on line 460.
The first method (WidgetController.tapAt) had not yet finished executing at the time that the second method (WidgetController._getElementPoint) was called. Since both are guarded, and the second was not a nested call inside the first, the first must complete its execution before the second can be called. Typically, this is achieved by putting an "await" statement in front of the call to the first.

When the first method (WidgetController.tapAt) was called, this was the stack:

#0      TestAsyncUtils.guard (package:flutter_test/src/test_async_utils.dart:70:54)
#1      WidgetController.tapAt (package:flutter_test/src/controller.dart:264:27)
#2      WidgetController.tap (package:flutter_test/src/controller.dart:259:12)
#3      FlutterDriverExtension._tap (package:flutter_driver/src/extension/extension.dart:460:19)
<asynchronous suspension>
#4      FlutterDriverExtension.call (package:flutter_driver/src/extension/extension.dart:270:53)
#5      BindingBase.registerServiceExtension.<anonymous closure> (package:flutter/src/foundation/binding.dart:547:32)
<asynchronous suspension>
#6      BindingBase.registerServiceExtension.<anonymous closure> (package:flutter/src/foundation/binding.dart)
#7      _runExtension (dart:developer-patch/developer.dart:84:23)
#0      TestAsyncUtils.guardSync (package:flutter_test/src/test_async_utils.dart:268:5)
#1      WidgetController._getElementPoint (package:flutter_test/src/controller.dart:817:20)
#2      WidgetController.getCenter (package:flutter_test/src/controller.dart:790:12)
#3      WidgetController.tap (package:flutter_test/src/controller.dart:259:18)
#4      FlutterDriverExtension._tap (package:flutter_driver/src/extension/extension.dart:460:19)
<asynchronous suspension>
#5      FlutterDriverExtension.call (package:flutter_driver/src/extension/extension.dart:270:53)
#6      BindingBase.registerServiceExtension.<anonymous closure> (package:flutter/src/foundation/binding.dart:547:32)
<asynchronous suspension>
#7      BindingBase.registerServiceExtension.<anonymous closure> (package:flutter/src/foundation/binding.dart)
#8      _runExtension (dart:developer-patch/developer.dart:84:23)


Exception: DriverError: Error in Flutter application: Uncaught extension error while executing tap: Guarded function conflict.
You must use "await" with all Future-returning test APIs.
The guarded method "tapAt" from class WidgetController was called from package:flutter_driver/src/extension/extension.dart on line 460.
Then, the "_getElementPoint" method (also from class WidgetController) was called again from package:flutter_driver/src/extension/extension.dart on line 460.
The first method (WidgetController.tapAt) had not yet finished executing at the time that the second method (WidgetController._getElementPoint) was called. Since both are guarded, and the second was not a nested call inside the first, the first must complete its execution before the second can be called. Typically, this is achieved by putting an "await" statement in front of the call to the first.

When the first method (WidgetController.tapAt) was called, this was the stack:

#0      TestAsyncUtils.guard (package:flutter_test/src/test_async_utils.dart:70:54)
#1      WidgetController.tapAt (package:flutter_test/src/controller.dart:264:27)
#2      WidgetController.tap (package:flutter_test/src/controller.dart:259:12)
#3      FlutterDriverExtension._tap (package:flutter_driver/src/extension/extension.dart:460:19)
<asynchronous suspension>
#4      FlutterDriverExtension.call (package:flutter_driver/src/extension/extension.dart:270:53)
#5      BindingBase.registerServiceExtension.<anonymous closure> (package:flutter/src/foundation/binding.dart:547:32)
<asynchronous suspension>
#6      BindingBase.registerServiceExtension.<anonymous closure> (package:flutter/src/foundation/binding.dart)
#7      _runExtension (dart:developer-patch/developer.dart:84:23)
#0      TestAsyncUtils.guardSync (package:flutter_test/src/test_async_utils.dart:268:5)
#1      WidgetController._getElementPoint (package:flutter_test/src/controller.dart:817:20)
#2      WidgetController.getCenter (package:flutter_test/src/controller.dart:790:12)
#3      WidgetController.tap (package:flutter_test/src/controller.dart:259:18)
#4      FlutterDriverExtension._tap (package:flutter_driver/src/extension/extension.dart:460:19)
<asynchronous suspension>
#5      FlutterDriverExtension.call (package:flutter_driver/src/extension/extension.dart:270:53)
#6      BindingBase.registerServiceExtension.<anonymous closure> (package:flutter/src/foundation/binding.dart:547:32)
<asynchronous suspension>
#7      BindingBase.registerServiceExtension.<anonymous closure> (package:flutter/src/foundation/binding.dart)
#8      _runExtension (dart:developer-patch/developer.dart:84:23)

My home_screen code

import 'package:flutter_driver/flutter_driver.dart';

class HomeScreen {
  FlutterDriver _driver;

  //Constructor
  HomeScreen(FlutterDriver driver) {
    this._driver = driver;
  }

  //Elements
  final btnHamburger = find.byType("InkWell");

  //Actions
  Future<void> waitBtnHamburger() async {
    await _driver.waitFor(btnHamburger);
    await print("Ok Hamburguer");
  }
}

My home_step code

import 'package:flutter_gherkin/flutter_gherkin.dart';
import 'package:gherkin/gherkin.dart';

import '../screens/home_screen.dart';

class HomeValidarScreen extends ThenWithWorld<FlutterWorld> {
  HomeValidarScreen()
      : super(StepDefinitionConfiguration()..timeout = Duration(seconds: 20));

  @override
  RegExp get pattern => RegExp(r"sou direcionado para a Home do aplicativo");

  @override
  Future<void> executeStep() async {
    HomeScreen homeScreen = new HomeScreen(world.driver);
    await homeScreen.waitBtnHamburger();
  }
}