在安卓中为使用Espresso进行片段隔离测试创建ViewModel的示例。

huangapple
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英文:

Creating ViewModel doubles in android for testing fragments in isolation with espresso

问题

我在使用Java开发Android应用。

我们的目标是在隔离环境中测试我们应用的一个片段（Fragment）。

我们的问题是，我们需要设置一个视图模型（view-model）的双重实例，以便创建有意义且值得测试的片段状态。

特别地，模拟我们的片段的模型视图（model-view）依赖于另一个视图模型。

在我们的研究中，我们了解到视图模型存储在特定的视图模型存储对象中，是否有一种通过Espresso在常规方式而非繁琐方式来操纵此存储位置的方法？也许可以通过与FragmentScenario对象的一些交互来实现？

下图说明了我们的情况。

在安卓中为使用Espresso进行片段隔离测试创建ViewModel的示例。

为了阐明我注入视图模型的方式，我附上了我的片段代码：

  1. public class CornerDetectionFragment extends Fragment {
  2.     private CornerDetectionViewModel cornerDetectionViewModel;
  3.     @Nullable
  4.     @Override
  5.     public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
  6.         cornerDetectionViewModel =
  7.                 ViewModelProviders.of(
  8.                         this,
  9.                         new CornerDetectionViewModelFactory(getActivity())
  10.                 ).get(CornerDetectionViewModel.class);
  11.         View root = inflater.inflate(R.layout.fragment_corner_detection, container, false);
  12.         ((TextView) root.findViewById(R.id.textView_relative_cirrent_location)).setText(
  13.                 "1/" + cornerDetectionViewModel.getNumberOfCornerDetectedCaptures().getValue()
  14.         );
  15.         return root;
  16.     }
  17. /*...*/
  18. }

还有视图模型工厂的代码：

  1. public class CornerDetectionViewModelFactory implements ViewModelProvider.Factory {
  2.     FragmentActivity activity;
  4.     public CornerDetectionViewModelFactory(FragmentActivity activity) {
  5.         this.activity = activity;
  6.     }
  8.     @NonNull
  9.     @Override
  10.     public <T extends ViewModel> T create(@NonNull Class<T> modelClass) {
  11.         return (T) ViewModelProviders.of(
  12.                 activity,
  13.                 new InitialFactory())
  14.                 .get(CornerDetectionViewModel.class
  15.                 );
  16.     }
  18.     private class InitialFactory implements ViewModelProvider.Factory{
  19.         @NonNull
  20.         @Override
  21.         public <T extends ViewModel> T create(@NonNull Class<T> modelClass) {
  22.             return (T) new CornerDetectionViewModel(
  23.                     new ImageProcessingFactory().create(),
  24.                     new ResolveAnswersViewModelFactory(activity)
  25.                             .create(ResolveAnswersViewModel.class)
  26.             );
  27.         }
  28.     }
  29. }

谢谢。

英文:

I'm working with android in Java.

Our goal is to test a fragment of our app in isolation.

Our problem is that we need to setup a view-model double to in order to create meaningful and test worthy fragment state.

In particular, the model-view that models our fragment depends on another view model.

In our research, we learned that view-models are stored in some specific view-model-store object, is there a way to manipulate this storage location from espresso in a conventional not to hacky way? via maybe some interaction with a FragmentScenrario object?

The figure ilustrates our situation.

在安卓中为使用Espresso进行片段隔离测试创建ViewModel的示例。

I'm appending my fragment code to clarify the way I'm injecting the view-model:

  1. public class CornerDetectionFragment extends Fragment {
  2.     private CornerDetectionViewModel cornerDetectionViewModel;
  3.     @Nullable
  4.     @Override
  5.     public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
  6.         cornerDetectionViewModel =
  7.                 ViewModelProviders.of(
  8.                         this,
  9.                         new CornerDetectionViewModelFactory(getActivity())
  10.                 ).get(CornerDetectionViewModel.class);
  11.         View root =inflater.inflate(R.layout.fragment_corner_detection, container, false);
  12.         ((TextView)root.findViewById(R.id.textView_relative_cirrent_location)).setText(
  13.                 &quot;1/&quot;+cornerDetectionViewModel.getNumberOfCornerDetectedCaptures().getValue()
  14.         );
  15.         return inflater.inflate(R.layout.fragment_corner_detection, container, false);
  16.     }
  17. /*...*/
  18. }

And also the code of the view-model factory:

  1. public class CornerDetectionViewModelFactory implements ViewModelProvider.Factory {
  2.     FragmentActivity activity;
  4.     public CornerDetectionViewModelFactory(FragmentActivity activity) {
  5.         this.activity = activity;
  6.     }
  8.     @NonNull
  9.     @Override
  10.     public &lt;T extends ViewModel&gt; T create(@NonNull Class&lt;T&gt; modelClass) {
  11.         return (T) ViewModelProviders.of(
  12.                 activity,
  13.                 new InitialFactory())
  14.                 .get(CornerDetectionViewModel.class
  15.                 );
  16.     }
  18.     private class InitialFactory implements ViewModelProvider.Factory{
  19.         @NonNull
  20.         @Override
  21.         public &lt;T extends ViewModel&gt; T create(@NonNull Class&lt;T&gt; modelClass) {
  22.             return (T)new CornerDetectionViewModel(
  23.                     new ImageProcessingFactory().create(),
  24.                     new ResolveAnswersViewModelFactory(activity)
  25.                             .create(ResolveAnswersViewModel.class)
  26.             );
  27.         }
  28.     }
  29. }

Thanks.

huangapple
  • 本文由 发表于 2020年3月16日 06:36:26
  • 转载请务必保留本文链接：https://java.coder-hub.com/60698368.html
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