如何为 android 的 API 编写单元测试用例？

Question

我想在开发和构建APK之前为我的一段代码编写一个单元测试用例，还需要通过所有单元测试用例。请建议我。

Answer 1

要编写测试用例，您需要遵循一些架构，如 MVP 或 MVVM，还需要使用 Junit 和 Mockito 测试框架Here 可以找到示例。

这是一个简单的例子，它可以帮助你。这里我使用 Retrofit 进行网络

活动

package com.ram.com.mvp_sample;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.ProgressBar;
import android.widget.Toast;

import com.ram.com.mvp_sample.modal.RemoteRepository;
import com.ram.com.mvp_sample.modal.Repository;
import com.ram.com.mvp_sample.modal.pojo.Example;

import java.util.List;

/**
 * A login screen that offers login via email/password.
 */
public class ImageListActivity extends AppCompatActivity implements Contract.View {


    private Contract.Presenter presenter;
    private ProgressBar mProgressView;
    private RecyclerView imageList;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_image_list);
        presenter = new Presenter(this, Repository.getInstance(RemoteRepository.getInstance()));
        mProgressView = findViewById(R.id.login_progress);
        imageList = findViewById(R.id.image_list);
        presenter.getImageList(new AppNetworkStatus(this));

    }


    @Override
    public void showProgressBar(boolean show) {
        mProgressView.setVisibility(show ? View.VISIBLE : View.GONE);
    }

    @Override
    public void showImageList(List<Example> example) {
        ImageListAdapter adapter = new ImageListAdapter(example);
        LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        imageList.setLayoutManager(layoutManager);
        imageList.setAdapter(adapter);
    }

    @Override
    public void showError(Object errorCode) {
        Toast.makeText(this, errorCode.toString(), Toast.LENGTH_LONG).show();
    }

    @Override
    public void setPresenter(Contract.Presenter presenter) {
        this.presenter = presenter;
    }
}

Repository 类：它将与 RemoteRepository 交互

package com.ram.com.mvp_sample;

import com.ram.com.mvp_sample.modal.DataSource;
import com.ram.com.mvp_sample.modal.Repository;
import com.ram.com.mvp_sample.modal.pojo.Example;

import java.util.List;

public class Presenter implements Contract.Presenter {

private Contract.View view;
private Repository repository;

public Presenter(Contract.View view, Repository storesRepository) {
    this.view = view;
    this.repository = storesRepository;
    this.view.setPresenter(this);
}

@Override
public void getImageList(NetworkStatus networkStatus) {
    view.showProgressBar(true);
    repository.getList(networkStatus, new DataSource.OnResponseCallBackListener() {
        @Override
        public void onSuccess(List<Example> data) {
            view.showProgressBar(false);
            view.showImageList(data);
        }

        @Override
        public void onError(Object error) {
            view.showProgressBar(false);
            view.showError(error);
        }
    });
}

@Override
public void start() {

}
}

RemoteRepository 类：这里会直接用Retrofit进行处理

 package com.ram.com.mvp_sample.modal;

import com.ram.com.mvp_sample.APIClient;
import com.ram.com.mvp_sample.ApiInterface;
import com.ram.com.mvp_sample.NetworkStatus;
import com.ram.com.mvp_sample.modal.pojo.Example;

import java.util.List;

import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;

public class RemoteRepository implements DataSource {

private static RemoteRepository INSTANCE = null;

private RemoteRepository() {
}

public static RemoteRepository getInstance() {
    if (INSTANCE == null) {
        INSTANCE = new RemoteRepository();
    }
    return INSTANCE;
}

@Override
public void getList(NetworkStatus networkStats, final OnResponseCallBackListener onResponseCallBackListener) {

    ApiInterface apiInterface = APIClient.getClient().create(ApiInterface.class);

    Call<List<Example>> call1 = apiInterface.getImageList();
    call1.enqueue(new Callback<List<Example>>() {
        @Override
        public void onResponse(Call<List<Example>> call, Response<List<Example>> response) {
            onResponseCallBackListener.onSuccess(response.body());

        }

        @Override
        public void onFailure(Call<List<Example>> call, Throwable t) {
            onResponseCallBackListener.onError(t.toString());

        }
    });
}
}

Presenter 类：Presenter 负责与 Repository 和 View 通信

package com.ram.com.mvp_sample;

import com.ram.com.mvp_sample.modal.DataSource;
import com.ram.com.mvp_sample.modal.Repository;
import com.ram.com.mvp_sample.modal.pojo.Example;

import java.util.List;

public class Presenter implements Contract.Presenter {

private Contract.View view;
private Repository repository;

public Presenter(Contract.View view, Repository storesRepository) {
    this.view = view;
    this.repository = storesRepository;
    this.view.setPresenter(this);
}

@Override
public void getImageList(NetworkStatus networkStatus) {
    view.showProgressBar(true);
    repository.getList(networkStatus, new DataSource.OnResponseCallBackListener() {
        @Override
        public void onSuccess(List<Example> data) {
            view.showProgressBar(false);
            view.showImageList(data);
        }

        @Override
        public void onError(Object error) {
            view.showProgressBar(false);
            view.showError(error);
        }
    });
}

@Override
public void start() {

}
}

presenter 类的测试用例

package com.ram.com.mvp_sample;

import com.ram.com.mvp_sample.modal.DataSource;
import com.ram.com.mvp_sample.modal.Repository;
import com.ram.com.mvp_sample.modal.pojo.Example;

import org.junit.Before;
import org.junit.Test;
import org.mockito.ArgumentCaptor;
import org.mockito.ArgumentMatchers;
import org.mockito.Captor;
import org.mockito.InOrder;
import org.mockito.Mock;
import org.mockito.Mockito;
import org.mockito.MockitoAnnotations;

import static org.mockito.ArgumentMatchers.anyString;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

public class PresenterTest {

private Presenter presenter;

@Mock
private Repository repository;

@Mock
private Contract.View view;

@Mock
private NetworkStatus networkStatus;

@Captor
private ArgumentCaptor<NetworkStatus> networkStatusArgumentCaptor;

@Captor
private ArgumentCaptor<DataSource.OnResponseCallBackListener> callBackListenerArgumentCaptor;

@Before
public void setUp() {
    MockitoAnnotations.initMocks(this);

    presenter = new Presenter(view, repository);
}

// Positive test
@Test
public void getImageList() {

    when(networkStatus.isOnline()).thenReturn(true);

    presenter.getImageList(networkStatus);

    verify(repository).getList(networkStatusArgumentCaptor.capture(), callBackListenerArgumentCaptor.capture());
    callBackListenerArgumentCaptor.getValue().onSuccess(ArgumentMatchers.<Example>anyList());

    InOrder inOrder = Mockito.inOrder(view);
    inOrder.verify(view).showProgressBar(true);
    inOrder.verify(view).showProgressBar(false);
    inOrder.verify(view).showImageList(ArgumentMatchers.<Example>anyList());

}

// Negative test
@Test
public void getImageListNetworkError() {

    when(networkStatus.isOnline()).thenReturn(false);

    presenter.getImageList(networkStatus);

    verify(repository).getList(networkStatusArgumentCaptor.capture(), callBackListenerArgumentCaptor.capture());
    callBackListenerArgumentCaptor.getValue().onError(anyString());

    InOrder inOrder = Mockito.inOrder(view);
    inOrder.verify(view).showProgressBar(true);
    inOrder.verify(view).showProgressBar(false);
    inOrder.verify(view).showError(anyString());

}

}

Repository 类的测试用例

package com.ram.com.mvp_sample;

import com.ram.com.mvp_sample.modal.DataSource;
import com.ram.com.mvp_sample.modal.RemoteRepository;
import com.ram.com.mvp_sample.modal.Repository;
import com.ram.com.mvp_sample.modal.pojo.Example;

import org.junit.Before;
import org.junit.Test;
import org.mockito.ArgumentCaptor;
import org.mockito.ArgumentMatchers;
import org.mockito.Captor;
import org.mockito.Mock;
import org.mockito.Mockito;
import org.mockito.MockitoAnnotations;

import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

public class RepositoryTest {

    private Repository repository;

    @Mock
    private RemoteRepository remoteRepository;

    @Mock
    private NetworkStatus networkStatus;

    @Captor
    private ArgumentCaptor<NetworkStatus> networkStatusArgumentCaptor;

    @Mock
    private DataSource.OnResponseCallBackListener callBackListener;
    @Captor
    private ArgumentCaptor<DataSource.OnResponseCallBackListener> callBackListenerArgumentCaptor;

    @Before
    public void setUp() {
        MockitoAnnotations.initMocks(this);
        repository = Repository.getInstance(remoteRepository);
    }

    @Test
    public void getImageList() {

        when(networkStatus.isOnline()).thenReturn(true);

        repository.getList(networkStatus, callBackListener);
        verify(remoteRepository).getList(networkStatusArgumentCaptor.capture(), callBackListenerArgumentCaptor.capture());
        callBackListenerArgumentCaptor.getValue().onSuccess(ArgumentMatchers.<Example>anyList());
        Mockito.verify(callBackListener).onSuccess(ArgumentMatchers.<Example>anyList());

        callBackListenerArgumentCaptor.getValue().onError("Some Error");
        Mockito.verify(callBackListener).onError("Some Error");

    }

}

如果您有任何疑问，请告诉我

Answer 2

我一直在使用Mockito 为不完全独立的组件编写单元测试用例。

开始使用 mockito 在您的项目中添加以下依赖项

    // required if you want to use Mockito for unit tests
    testCompile 'org.mockito:mockito-core:2.7.22'
    // required if you want to use Mockito for Android tests
    androidTestCompile 'org.mockito:mockito-android:2.7.22'

单元测试在单个线程上工作，而 api 调用发生在某个不同的线程上。所以你需要模拟来自服务器的响应。为此，您可以使用 mockito。

所以通常在 api 调用中，您只需要检查来自服务器的响应是否被解析到您的 pojo 中。但是在单元测试中获得服务器响应是不可能的。因此，您需要模拟响应。对于该模拟，请使用 Mockito。