我如何使用Mockito的匕首注射？

Question

我正在尝试为Android应用编写单元测试，该应用使用dagger进行ViewModel注入。我似乎没有为JUnitTest注射工作。当我使用@Mock注入gapiService时，Retrofit返回null调用请求：

    final MutableLiveData<GissuesResponse> lData = new MutableLiveData<>();
    Call<List<Issue>> callRequest = gapiService.getIssues(owner, repo);

我的整个项目位于http://github.com/CodingWords/Gissues

不确定如何在JUnitTest中正确设置ViewModel以进行注入。谢谢！

Here is my JUnitTest

import android.arch.lifecycle.ViewModelProvider;
import android.arch.lifecycle.ViewModelProviders;

import com.codingwords.sobrien.gissues.api.GAPIService;
import com.codingwords.sobrien.gissues.model.SearchIssuesModel;
import com.codingwords.sobrien.gissues.repo.IssueRepository;
import com.codingwords.sobrien.gissues.vm.GissuesViewModel;

import org.junit.Before;
import org.junit.Test;
import org.mockito.Mock;
import org.mockito.Mockito;
import org.mockito.MockitoAnnotations;

import javax.inject.Inject;


public class GissuesUnitTest {

    @Mock //Mock annotation tells Mockito to give a mocked object
    GissuesScreen gissuesScreen;

    @Mock
    GAPIService gapiService;

    //class that is being tested
    @Inject
    ViewModelProvider.Factory viewModelFactory;
    IssueRepository gissuesRepo;
    GissuesViewModel gissuesViewModel;

    final String dummyOwner = "ethereum";
    final String dummyRepo = "solidity";


    @Before
    public void setupGissuesViewModel(){
        //this function will be called before all tests are run
        // call this function to init all objects annotated with @mock
        MockitoAnnotations.initMocks(this);
        gissuesRepo = new IssueRepository();
        gissuesRepo.setGapiService(gapiService);
        gissuesViewModel = new GissuesViewModel(gissuesRepo);
        gissuesViewModel.setGissuesScreen(gissuesScreen);
        SearchIssuesModel sim = new SearchIssuesModel();
        gissuesViewModel.setSearchModel(sim);
        //we create an instance of the class to be tested by passing the mocked objec


    }

    @Test
    public void requestIssuesWithEmptyOwner_showsOwnerError(){
        gissuesViewModel.getSearchModel().setOwner("");
        gissuesViewModel.pullIssues();
        //use mockito to verify that the showOwnerError() method is called in the screen object
        Mockito.verify(gissuesScreen).showOwnerError();
    }

    @Test
    public void requestIssuesWithEmptyRepo_showsRepoError(){
        gissuesViewModel.getSearchModel().setOwner("ethereum");
        gissuesViewModel.getSearchModel().setRepo("");
        gissuesViewModel.pullIssues();
        Mockito.verify(gissuesScreen).showRepoError();
    }

    @Test
    public void requestIssuesWithEmptyList_showsIssuesNotFound(){
        gissuesViewModel.getSearchModel().setOwner("ethereum");
        gissuesViewModel.getSearchModel().setRepo("ethereum");
        gissuesViewModel.pullIssues();
        Mockito.verify(gissuesScreen).showIssuesNotFound();
    }


}

这是IssueRepo

public class IssueRepository implements IssueRepo {
    @Inject
    public IssueRepository() {
    }

    @Inject
    GAPIService gapiService;


    @Override
    public LiveData<GissuesResponse> receiveIssues(String owner, String repo) {
        final MutableLiveData<GissuesResponse> lData = new MutableLiveData<>();
        // callRequest is returned as null because gapiService was mock object?
        Call<List<Issue>> callRequest = gapiService.getIssues(owner, repo);
        callRequest.enqueue(new Callback<List<Issue>>() {
            @Override
            public void onResponse(Call<List<Issue>> call, Response<List<Issue>> response) {
                lData.setValue(new GissuesResponse(response.body()));
            }

            @Override
            public void onFailure(Call<List<Issue>> call, Throwable t) {
                lData.setValue(new GissuesResponse(t));
            }
        });
        return lData;
    }

    public GAPIService getGapiService() {
        return gapiService;
    }

    public void setGapiService(GAPIService gapiService) {
        this.gapiService = gapiService;
    }
}

这是视图模型

import android.arch.lifecycle.LiveData;
import android.arch.lifecycle.MediatorLiveData;
import android.arch.lifecycle.ViewModel;
import android.support.annotation.NonNull;

import com.codingwords.sobrien.gissues.GissuesScreen;
import com.codingwords.sobrien.gissues.entity.GissuesResponse;
import com.codingwords.sobrien.gissues.model.SearchIssuesModel;
import com.codingwords.sobrien.gissues.repo.IssueRepo;

import javax.inject.Inject;

/**
 * Created by Administrator on 2/19/2018.
 */

public class GissuesViewModel extends ViewModel {

    private IssueRepo issueRepository;
    private MediatorLiveData<GissuesResponse> gapiResponse;
    private SearchIssuesModel searchModel;
    private GissuesScreen gissuesScreen;


    @Inject
    public GissuesViewModel(IssueRepo repository) {
        this.issueRepository = repository;
        this.gapiResponse = new MediatorLiveData<GissuesResponse>();

    }

    public MediatorLiveData<GissuesResponse> getGapiResponse() {
        return gapiResponse;
    }

    public void pullIssues(){
        if (getSearchModel() != null){
            if ((getSearchModel().getOwner() == null) || (getSearchModel().getOwner().length() < 2)){
                gissuesScreen.showOwnerError();
            } else if  ((getSearchModel().getRepo() == null) || (getSearchModel().getRepo().length() < 2)) {
                gissuesScreen.showRepoError();
            } else {
                pullIssues(getSearchModel().getOwner(), getSearchModel().getRepo());
            }
        }
    }

    public void pullIssues(@NonNull String user, String repo) {
        LiveData<GissuesResponse> issuesSource = issueRepository.receiveIssues(user, repo);
        gapiResponse.addSource(
                                issuesSource,
                                gapiResponse -> {
                    if (this.gapiResponse.hasActiveObservers()) {
                        this.gapiResponse.removeSource(issuesSource);
                    }
                    this.gapiResponse.setValue(gapiResponse);
                }
        );
    }

    public SearchIssuesModel getSearchModel() {
        return searchModel;
    }

    public void setSearchModel(SearchIssuesModel searchModel) {
        this.searchModel = searchModel;
    }

    public GissuesScreen getGissuesScreen() {
        return gissuesScreen;
    }

    public void setGissuesScreen(GissuesScreen gissuesScreen) {
        this.gissuesScreen = gissuesScreen;
    }
}