title: testDeviceId's are not working in google-mobile-ads flutter
body: <p>I was trying to set my test device id with the requestConfiguration. For checking whether setup for testdevice is successful, I filtered <code>logcat</code> in android studio with <code>setTestDeviceIds</code> but it's showing me the following log</p>
  <pre><code>2021-03-31 04:17:36.907 27185-27185/? I/Ads: Use RequestConfiguration.Builder().setTestDeviceIds(Arrays.asList(&quot;xxxxxxxxxxxxxxxxxxx&quot;)) to get test ads on this device.
  </code></pre>
  <p>So setting up for test device are not working and I can't test with real ads. As I'm passing testDeviceId's this log was supposed to not appear. You can see I'm passing <code>testDeviceId</code>'s for both in <code>RequestConfiguration</code> and <code>bannerAd</code>.</p>
  <h3>Steps to reproduce</h3>
  <p>Here is my <code>main.dart</code> file</p>
  <pre class="lang-dart prettyprint-override"><code>import 'package:flutter/material.dart';
  import 'package:google_mobile_ads/google_mobile_ads.dart';
  import 'package:provider/provider.dart';
  import 'package:us/global/theme/app_themes.dart';
  import 'package:us/utils/ad_helper.dart';
  
  void main() {
    WidgetsFlutterBinding.ensureInitialized();
  
    MobileAds.instance.initialize().then((InitializationStatus status) {
      print('Initialization done: ${status.adapterStatuses}');
      MobileAds.instance
          .updateRequestConfiguration(RequestConfiguration(
          testDeviceIds: AdHelper.allTestDevices));
    });
  
  
    runApp(
        MyApp()
    );
  }
  
  
  class MyApp extends StatelessWidget {
    @override
    Widget build(BuildContext context) {
      return ChangeNotifierProvider&lt;ThemeChanger&gt;(
        create: (_) =&gt; ThemeChanger(),
        child: new MaterialAppWithTheme(),
      );
    }
  }
  
  class MaterialAppWithTheme extends StatelessWidget {
    @override
    Widget build(BuildContext context) {
      final theme = Provider.of&lt;ThemeChanger&gt;(context);
  
      return MaterialApp(
        title: 'Const',
        debugShowCheckedModeBanner: false,
        theme: theme.getDarkTheme ? ThemeData.dark():ThemeData.light(),
        home: HomeScreen(),
      );
    }
  }
  
  class HomeScreen extends StatefulWidget {
    @override
    _HomeScreenState createState() =&gt; _HomeScreenState();
  }
  
  class _HomeScreenState extends State&lt;HomeScreen&gt; {
  
    static final AdRequest request = AdRequest(
      testDevices: AdHelper.allTestDevices,
    );
  
    BannerAd _bannerAdd;
    bool _isBannerAdLoaded = false;
  
    Future&lt;InitializationStatus&gt; _initGoogleMobileAds() {
      // TODO: Initialize Google Mobile Ads SDK
      return MobileAds.instance.initialize();
    }
  
    @override
    void initState() {
      super.initState();
  
  
      _bannerAdd = BannerAd(
        adUnitId: AdHelper.homePageBannerAd,
        size: AdSize.banner,
        request: request,
        listener: AdListener(
          onAdLoaded: (_) {  // Future&lt;SharedPrefData&gt; _setDarkMode(bool darkMode) async{
            //   SharedPreferences prefs = await SharedPreferences.getInstance();
            //   log.i('Current dark mode  $darkMode.');
            //   await prefs.setBool('darkmode', darkMode);
            //   log.i('Dark mode toggled successfully');
            //   return await getPersistedData();
            // }
            setState(() {
              _isBannerAdLoaded = true;
            });
          },
          onAdFailedToLoad: (ad, error) {
            // Releases an ad resource when it fails to load
            ad.dispose();
  
            print('Ad load failed (code=${error.code} message=${error.message})');
          },
        ),
      );
  
      _bannerAdd.load();
  
    }
    
  
    @override
    Widget build(BuildContext context) {
  
      //this gonna give us total height and with of our device
      return Scaffold(
        // bottomNavigationBar: BottomNavBar(),
        body: Stack(
          children: &lt;Widget&gt;[
            SafeArea(
              child: Padding(
                padding: const EdgeInsets.symmetric(horizontal: 20),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: &lt;Widget&gt;[
                    this._isBannerAdLoaded? Container(
                      margin: EdgeInsets.only(bottom: 35),
                      height: 72.0,
                      alignment: Alignment.center,
                      child: AdWidget(ad: _bannerAdd),
                    ):Text('')
                  ],
                ),
              ),
            )
          ],
        ),
      );
    }
  }
  
  
  
  </code></pre>
  <p>Here is my <code>adhelper.dart</code> file</p>
  <pre class="lang-dart prettyprint-override"><code>import 'dart:io';
  
  class AdHelper{
  
    static String TEST_BANNER_AD = &quot;ca-app-pub-3940256099942544/6300978111&quot;;
  
   static String get homePageBannerAd{
     if(Platform.isAndroid){
       return TEST_BANNER_AD;
     }
     else if(Platform.isIOS){
       return TEST_BANNER_AD;
     }
     else
       throw new UnsupportedError(&quot;Platform is not supported..&quot;);
   }
  
   static List&lt;String&gt; get allTestDevices{
  
         String MY_REDMI_NOTE_9=&quot;xxxxxxxxxxx&quot;;
  
  
     return [MY_REDMI_NOTE_9];
    }
  
  }
  </code></pre>
  <h3>Flutter doctor</h3>
  <p>Run <code>flutter doctor</code> and paste the output below:</p>
  Click To Expand
  <pre><code>Doctor summary (to see all details, run flutter doctor -v):
  [✓] Flutter (Channel stable, 2.0.1, on Linux, locale en_US.UTF-8)
  [!] Android toolchain - develop for Android devices (Android SDK version 30.0.2)
      ✗ Android license status unknown.
        Run `flutter doctor --android-licenses` to accept the SDK licenses.
        See https://flutter.dev/docs/get-started/install/linux#android-setup for more details.
  [✓] Chrome - develop for the web
  [✓] Android Studio (version 3.5)
  [✓] IntelliJ IDEA Ultimate Edition (version 2020.2)
  [✓] VS Code (version 1.54.3)
  [✓] Connected device (2 available)
  
  ! Doctor found issues in 1 category.
  </code></pre>
  
  <hr />
  <h3>Flutter dependencies</h3>
  <p>Run <code>flutter pub deps -- --style=compact</code> and paste the output below:</p>
  Click To Expand
  <pre><code>Dart SDK 2.12.0
  Flutter SDK 2.0.1
  us_constitution 1.0.0+1
  
  dependencies:
  - dynamic_text_highlighting 2.2.0 [flutter]
  - flutter 0.0.0 [characters collection meta typed_data vector_math sky_engine]
  - flutter_svg 0.19.3 [flutter meta path_drawing vector_math xml]
  - flutter_xlider 3.4.0 [flutter]
  - google_mobile_ads 0.11.0+4 [meta flutter]
  - logger 1.0.0
  - path_provider 2.0.1 [flutter path_provider_platform_interface path_provider_macos path_provider_linux path_provider_windows]
  - provider 5.0.0 [collection flutter nested]
  - shared_preferences 2.0.5 [meta flutter shared_preferences_platform_interface shared_preferences_linux shared_preferences_macos shared_preferences_web shared_preferences_windows]
  - sqflite 1.3.2+4 [flutter sqflite_common path]
  - url_launcher 6.0.3 [flutter url_launcher_platform_interface url_launcher_linux url_launcher_macos url_launcher_windows url_launcher_web]
  
  dev dependencies:
  - flutter_test 0.0.0 [flutter test_api path fake_async clock stack_trace vector_math async boolean_selector characters charcode collection matcher meta source_span stream_channel string_scanner term_glyph typed_data]
  
  transitive dependencies:
  - async 2.5.0 [collection]
  - boolean_selector 2.1.0 [source_span string_scanner]
  - characters 1.1.0
  - charcode 1.2.0
  - clock 1.1.0
  - collection 1.15.0
  - convert 2.1.1 [charcode typed_data]
  - fake_async 1.2.0 [clock collection]
  - ffi 1.0.0
  - file 6.1.0 [meta path]
  - flutter_web_plugins 0.0.0 [flutter js characters collection meta typed_data vector_math]
  - js 0.6.3
  - matcher 0.12.10 [stack_trace]
  - meta 1.3.0
  - nested 1.0.0 [flutter]
  - path 1.8.0
  - path_drawing 0.4.1+1 [vector_math meta path_parsing flutter]
  - path_parsing 0.1.4 [vector_math meta]
  - path_provider_linux 2.0.0 [path xdg_directories path_provider_platform_interface flutter]
  - path_provider_macos 2.0.0 [flutter]
  - path_provider_platform_interface 2.0.0 [flutter meta platform plugin_platform_interface]
  - path_provider_windows 2.0.0 [path_provider_platform_interface meta path flutter ffi win32]
  - petitparser 3.1.0 [meta]
  - platform 3.0.0
  - plugin_platform_interface 1.0.3 [meta]
  - process 4.1.0 [file path platform]
  - shared_preferences_linux 2.0.0 [flutter file meta path path_provider_linux shared_preferences_platform_interface]
  - shared_preferences_macos 2.0.0 [shared_preferences_platform_interface flutter]
  - shared_preferences_platform_interface 2.0.0 [flutter]
  - shared_preferences_web 2.0.0 [shared_preferences_platform_interface flutter flutter_web_plugins meta]
  - shared_preferences_windows 2.0.0 [shared_preferences_platform_interface flutter file meta path path_provider_platform_interface path_provider_windows]
  - sky_engine 0.0.99
  - source_span 1.8.0 [charcode collection path term_glyph]
  - sqflite_common 1.0.3+1 [synchronized path meta]
  - stack_trace 1.10.0 [path]
  - stream_channel 2.1.0 [async]
  - string_scanner 1.1.0 [charcode source_span]
  - synchronized 2.2.0+2
  - term_glyph 1.2.0
  - test_api 0.2.19 [async boolean_selector collection meta path source_span stack_trace stream_channel string_scanner term_glyph matcher]
  - typed_data 1.3.0 [collection]
  - url_launcher_linux 2.0.0 [flutter]
  - url_launcher_macos 2.0.0 [flutter]
  - url_launcher_platform_interface 2.0.1 [flutter plugin_platform_interface]
  - url_launcher_web 2.0.0 [url_launcher_platform_interface meta flutter flutter_web_plugins]
  - url_launcher_windows 2.0.0 [flutter]
  - vector_math 2.1.0
  - win32 2.0.0 [ffi]
  - xdg_directories 0.2.0 [meta path process]
  - xml 4.5.1 [collection convert meta petitparser]
  
  </code></pre>
  
  <hr />