Getting error while accessing the room database in

问题:

I am using room database in my app. I have Login feature in my app, where after taking userId & password, on click of Login button I am calling API and storing the response data in room database table after getting a successful callback response from API.

Now I want to write integration test cases for database data, where I am using mockWebServer to mock the API response and storing that in the room database table.

And later I am fetching the DB values & testing whether those are stored properly or not but I am getting below error

java.lang.IllegalStateException: Cannot access database on the main thread since it may potentially lock the UI for a long period of time.

On this line authentication = authenticationDao.getAuthInformation();

Below is my test cases code:

@RunWith(AndroidJUnit4.class)
@FixMethodOrder(MethodSorters.NAME_ASCENDING)
public class TestLogin {

@Rule
public InstantTaskExecutorRule mInstantTaskExecutorRule = new InstantTaskExecutorRule();
@Rule
public ActivityTestRule<LoginActivity> activityTestRule = new ActivityTestRule<>(LoginActivity.class, true, false);
@Rule
public MockWebServerTestRule mockWebServerTestRule = new MockWebServerTestRule();
@Mock
Application application;
LoginViewModel loginViewModel;
AppDatabase appDatabase;
AuthenticationDao authenticationDao;
Authentication authentication;

@Before
public void setUp() throws Exception {
    MockitoAnnotations.initMocks(this);
    loginViewModel = new LoginViewModel(application);
    ApiUrls.TOKEN = mockWebServerTestRule.mockWebServer.url("/").toString();

    appDatabase = Room.inMemoryDatabaseBuilder(InstrumentationRegistry.getContext(),
            AppDatabase.class).build();
    authenticationDao = appDatabase.authenticationDao();

    activityTestRule = new ActivityTestRule<>(LoginActivity.class, true, true);
    String fileName = "valid_login_response.json";
    mockWebServerTestRule.mockWebServer.enqueue(new MockResponse()
            .setBody(RestServiceTestHelper.getStringFromFile(getContext(), fileName))
            .setResponseCode(HttpURLConnection.HTTP_OK));

    Intent intent = new Intent();
    activityTestRule.launchActivity(intent);

    loginViewModel.userName.postValue("Elon");
    loginViewModel.password.postValue("Musk123");
    loginViewModel.getAuthenticateTokenData();
    mockWebServerTestRule.mockWebServer.takeRequest();


}

@Test
public void a_testDbEntryOnValidResponse() {
    authentication = authenticationDao.getAuthInformation();

    String issueTime = authentication.getIssueDateTime();
    String expirationTime = authentication.getExpireDateTime();
    String refreshToken = authentication.getRefreshToken();

    Assert.assertEquals("Tue, 16 Apr 2019 10:39:20 GMT", issueTime);
    Assert.assertEquals("Tue, 16 Apr 2019 10:54:20 GMT", expirationTime);
    Assert.assertEquals("e2b4dfd7205587745aa3100af9a0b", refreshToken);

}
}

Below is my AppDatabase class:

@Database(entities = {Authentication.class, UserProfile.class}, version = 1, exportSchema = false)

public abstract class AppDatabase extends RoomDatabase {

private static AppDatabase INSTANCE;

public static AppDatabase getAppDatabase(Context context) {
    if (INSTANCE == null) {
        INSTANCE =
                Room.databaseBuilder(context,
                        AppDatabase.class,
                        "myapp-database")
                        .allowMainThreadQueries()
                        .build();
    }
    return INSTANCE;
}

public abstract AuthenticationDao authenticationDao();

public abstract UserProfileDao userProfileDao();
}

What could be the issue? Is my test case right?

Thank you in advance.