Let's start changing the repository to trigger an exception(typo in the orderby clause):

DatabaseBooksRepository.java

public class DatabaseBooksRepository implements BooksRepository {
  private final DatabaseHelper databaseHelper;
  public DatabaseBooksRepository(Content context) {
   databaseHelper = OpenHelperManager.getHelper(context, DatabaseHelper.class);
  }

  @Override
  public List<Book> getBooks(){
    try{
      return databaseHelper.getbookDaO().queryBuilder()
               .orderBy("orderXXX", tru)
               .query();
    } catch {
      throw new RuntimeException("boom");
    }
  }
}

the new scenario for testing it would look like this: BooksActivityPresenterTest.java

import org.junit.Test;
import org.junit.Asserts;
import org.junit.runner.RunWith;
import org.mockito.junit.MockitoJUnitRunner;

public class BooksActivityPresenterTest {
 
 @Rule
 public MockitoRule mockitoRule = MockitoJUnit.rule();

 @Mock
 BooksRepository booksRepository;

 @Mock
 BooksActivityView view;
 
 BooksActivityPresenter presenter;

 @Before
 public void setUp() { presenter = new BooksActivityPresenter(view, booksRepository); }

 @Test
 public void shouldHandleAnException() {

  Mockito.when(booksRepository.getBooks())
                              .thenThrown(new RuntimeException("boom")));
  
  presenter.loadBooks();

  Mockito.verify(view).displayError();
 }
}

Now we need to implement this new displayError method: BooksActivityView.js

public interface BookActivityView {
  void displayBooks(List<Book> bookList);

  void displayNoBooks();

  void displayError();
}

And as our BooksActivity implements this interface we need to declare there our view method and the logic for that:

BooksActivity.java

public class BooksActivity extend BaseActivity implements BooksActivityView { private BooksActivityPresenter presenter; @override protected void onCreate(...){ .... }

@Override public void displayBooks(List bookList) { ... }

@Override public void displayNoBooks() { ... };

@Override public void displayError() { Toast.makeText(this, "Errror accessing data", Toast.LENGTH_SHORT).show(); }; }

And we need to reflect this change on the main:
BooksActivityPresenter.java

public class BooksActivityPresenter { public BooksActivityPresenter(BooksActivityView view, BooksRepository booksRepository) { this.view = view; this.booksRepository = booksRepository }

public void loadBooks(){ List listBooks; try { listBooks = booksRepository.getBooks(); // Here the presenter does not know anything about the repository // the presenter just wait for getting an array of values and that's it if(listBooks.isEmpty()){ view.displayNoBooks(); } else { view.displayBooks(bookList); } } catch(Exception e) { view.displayError(); }

} }