android - 如何在使用 IdlingResource 获取数据的 fragment 中使用 Espresso 测试 Recycler View

Question

会的，我有一个包含 MainFragment 的 MainActivity，MainFragment 实现了一个 RecipeDataFetcher 回调接口(interface)，将通过 Volley/network 获取的数据带到 RecipeDataFetcher 类中。MainFragment 有一个 recyclerview，它应该显示几个食谱卡片

-我需要对 RecyclerView 项目执行测试

这是我的主要 fragment `公共(public)类

MainFragment extends Fragment implements RecipesRecyclerAdapter.OnRecipeItemSelected,
        RecipesDataFetcher.RecipesFetcherDataListener {

    private View v;
    private RecipesDataFetcher recipesDataFetcher;
    private OnFragmentInteractionListener mListener;

private RecyclerView recyclerView;
private RecipesRecyclerAdapter recipesRecyclerAdapter;
private Recipes mRecipes;
private RecyclerView.LayoutManager layoutManager;


private SimpleIdlingResource mIdlingResource;


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    v = inflater.inflate(R.layout.fragment_main, container, false);
    mRecipes = new Recipes();
    recyclerView = (RecyclerView) v.findViewById(R.id.rv_recipes);
    if (mTwoPanel) {
        layoutManager = new GridLayoutManager(getActivity(), 2);
    } else {
        layoutManager = new LinearLayoutManager(getActivity());
    }

    recipesRecyclerAdapter = new RecipesRecyclerAdapter(this, mRecipes);
    recyclerView.setLayoutManager(layoutManager);
    recyclerView.setAdapter(recipesRecyclerAdapter);
    return v;
}

@VisibleForTesting
@NonNull
public SimpleIdlingResource getIdlingResource() {
    if (mIdlingResource == null) {
        mIdlingResource = new SimpleIdlingResource();
    }
    return mIdlingResource;
}



   @Override
    public void onSaveInstanceState(Bundle outState) {
//        super.onSaveInstanceState(outState);
    }
@Override
public void onAttach(Context context) {
    super.onAttach(context);
    if (context instanceof OnFragmentInteractionListener) {
        mListener = (OnFragmentInteractionListener) context;
    } else {
        throw new RuntimeException(context.toString()
                + " must implement OnFragmentInteractionListener");
    }
}

@Override
public void onDetach() {
    super.onDetach();
    mListener = null;
}

@Override
public void onItemSelected(int itemPosition) {
    mListener.onFragmentInteraction(mRecipes.get(itemPosition), mRecipes.size());
}

@Override
public void onResume() {
    super.onResume();
    if (mRecipes.isEmpty()) {
        getData();
    }
}

@Override
public void onConnectionFailure() {
    if (!checkOnlineState(getActivity())) {
        Logging.shortToast(getActivity(), getString(R.string.internet_error));
    } else {
        Logging.shortToast(getActivity(), getString(R.string.server_error));
    }
}

private void getData() {
    recipesDataFetcher = new RecipesDataFetcher(getActivity(), this);
    recipesDataFetcher.getRecipes(mIdlingResource);
}

@Override
public void onConnectionDone(Recipes recipes) {

    mRecipes.addAll(recipes);
    recipesRecyclerAdapter.notifyDataSetChanged();

    //TODO: Do bulk inset in a background thread and for once
    ContentValues[] contentValues = new ContentValues[recipes.size()];
    for (int i = 0; i < recipes.size(); i++) {
        ContentValues contentValue = new ContentValues();
        Gson gson = new Gson();
        String ingredients = gson.toJson(recipes.get(i).getIngredients());
        String steps = gson.toJson(recipes.get(i).getSteps());
        contentValue.put(COLUMN_RECIPE_INGREDIENTS, ingredients);
        contentValue.put(COLUMN_RECIPE_STEPS, steps);
        contentValue.put(COLUMN_RECIPE_SERVINGS, recipes.get(i).getServings());
        contentValue.put(COLUMN_RECIPE_IMAGE, recipes.get(i).getImage());
        contentValue.put(COLUMN_RECIPE_NAME, recipes.get(i).getName());
        contentValues[i] = contentValue;
    }

    getContext().getContentResolver().bulkInsert(CONTENT_URI, contentValues);

    if(mIdlingResource!=null){
        mIdlingResource.setIdleState(true);
    }

}


public interface OnFragmentInteractionListener {
    void onFragmentInteraction(Recipe recipe, int size);
}`

这是我的 dataFetching 类

public class RecipesDataFetcher extends BaseDataFetcher {
    public RecipesDataFetcher(Context context, BaseDataFetcherListener mListener) {
        super(context, mListener);
    }



    public void getRecipes(SimpleIdlingResource simpleIdlingResource) {
            if(simpleIdlingResource!=null){
            simpleIdlingResource.setIdleState(false);}
        String URL = BaseURL;
    Logging.log("getCountries: " + URL);
    JsonArrayRequest jsonObjReq = new JsonArrayRequest(URL, (JSONArray jsonArr) -> {
        Logging.log("getCountries response: " + jsonArr.toString());
        Recipes recipes = new Recipes(jsonArr);
        ((RecipesFetcherDataListener) mListener).onConnectionDone(recipes);
        if(simpleIdlingResource!=null){
            simpleIdlingResource.setIdleState(true);
        }
    }, this.errorListener);
    retryPolicy(jsonObjReq);
    getReQ().add(jsonObjReq);
}

public interface RecipesFetcherDataListener extends BaseDataFetcherListener {
    void onConnectionDone(Recipes recipes);
}

这是我的测试类

 @RunWith(AndroidJUnit4.class)
    public class MyFragmentTest {   

        private SimpleIdlingResource mIdlingResource;

    @Rule
    public FragmentTestRule<MainFragment> mFragmentTestRule = new FragmentTestRule<>(MainFragment.class);

    @Before
    public void registerIdlingResource() {
        // Launch the activity to make the fragment visible
        mFragmentTestRule.launchActivity(null);
         mIdlingResource = mFragmentTestRule.getFragment().getIdlingResource();
        Espresso.registerIdlingResources(mIdlingResource);
    }

    @Test
    public void fragment_can_be_instantiated() {


        // Then to test item in position 0
        onView(withId(R.id.rv_recipes))
                .perform(RecyclerViewActions.actionOnItemAtPosition(0, click()));
    }

    //  unregister resources
    @After
    public void unregisterIdlingResource() {
        if (mIdlingResource != null) {
            Espresso.unregisterIdlingResources(mIdlingResource);
        }
    }
}

最后 here是整个代码项目，请让我知道我到底做错了什么 :D，非常感谢您的帮助。

Answer 1

错误解释

参观完您的存储库并运行 MyFragmentTest 测试类

我遇到了两个错误

1. java.lang.RuntimeException: com.baking.www.baking.utilities.TestActivity@1d6e5b2 必须实现 OnFragmentInteractionListener

发生这种情况是因为在 FragmentTestRule 类中，您扩展了 ActivityTestRule <TestActivity>，其中 TestActivity 未实现 OnFragmentInteractionListener，因此解决方案是您拥有扩展已经实现此接口(interface)的 MainActivity，因此此类应如下所示:

public class FragmentTestRule<F extends Fragment> extends ActivityTestRule<MainActivity> {

private final Class<F> mFragmentClass;
private F mFragment;

public FragmentTestRule(final Class<F> fragmentClass) {
    super(MainActivity.class, true, false);
    mFragmentClass = fragmentClass;
}
.....

1. java.lang.NullPointerException:尝试在空对象引用上调用虚拟方法“com.baking.www.baking.IdlingResource.SimpleIdlingResource com.baking.www.baking.fragments.MainFragment.getIdlingResource()”

发生这种情况是因为在您的 MyFragmentTest注释 @Before 在任何开始之前被调用，这导致您的 fragment 尚未创建，这使得这一行没有意义

 mIdlingResource = mFragmentTestRule.getFragment().getIdlingResource();

所以在我看来:不要使用 fragment 。 Activity 更容易测试。您可以单独测试每个 Activity 。在大多数情况下，Fragments 与 Activity 相比没有任何优势。 fragment 只会使实现和测试更加困难。

使用 volley 运行空闲资源的替代解决方案

(a) 在MainActivity.java

添加这些行

@Nullable
public SimpleIdlingResource mIdlingResource;

@VisibleForTesting
@NonNull
public SimpleIdlingResource getIdlingResource() {
    if (mIdlingResource == null) {
        mIdlingResource = new SimpleIdlingResource();
    }
    return mIdlingResource;
}

并在您的 onCreate 中调用此方法 getIdlingResource();从 idlingResouce 中获取实例。

(b) 在 MainFragment.java 中

• 删除类变量mIdlingResource，它是getMethod
• 您会发现 mIdlingResource 的错误
• 用 ((MainActivity)getActivity()).mIdlingResource 替换任何 mIdlingResource

(c) 最后这是新的 MainActivityTest

@RunWith(AndroidJUnit4.class)
public class MainActivityTest {

@Rule
public ActivityTestRule<MainActivity> mActivityTestRule =
        new ActivityTestRule<>(MainActivity.class);

private IdlingResource mIdlingResource;


// Registers any resource that needs to be synchronized with Espresso before the test is run.
@Before
public void registerIdlingResource() {
    mIdlingResource = mActivityTestRule.getActivity().getIdlingResource();
    // To prove that the test fails, omit this call:
    Espresso.registerIdlingResources(mIdlingResource);
}

@Test
public void idlingResourceTest() {
    onView(withId(R.id.rv_recipes)).check(matches(isDisplayed()));
    onView(withId(R.id.rv_recipes))
            .perform(RecyclerViewActions.actionOnItemAtPosition(0, click()));
}

// Remember to unregister resources when not needed to avoid malfunction.
@After
public void unregisterIdlingResource() {
    if (mIdlingResource != null) {
        Espresso.unregisterIdlingResources(mIdlingResource);
    }
}

}

抱歉，回答太长了希望我能帮上忙 :) :)