验证是否在 Android Studio 测试（JUnit 和 mockito）中调用视图方法

Question

Sorry for silly questions, I am new to Testing in Android studio and not able to find solutions online. Well I am trying to verify that a method in view is called whenever the method in presenter is called or not.

    @Override
    public void chooseImage() {
        Intent intent = new Intent();
        intent.setType("image/*");
        intent.setAction(Intent.ACTION_GET_CONTENT);
        view.galleryImageSelected(intent);
    }

The above snippet is a method in my Presenter Class, and as you can see, I am calling a interface method of view from this function. Now I have to verify/test that this snippet works perfectly.

@RunWith(MockitoJUnitRunner.class)
public class ExampleUnitTest {

    @Mock
    private File storageDir;
    @Mock
    private PackageManager pManager;
    @Mock
    private Context appContext;
    @Mock
    private MainActivityContract.View view;
    @InjectMocks
    private MainActivityPresenter presenter;
    @Captor
    private ArgumentCaptor<Intent> captor;

    @Before
    public void setUp() throws Exception {
        presenter = new MainActivityPresenter(storageDir, pManager, appContext, view);
    }

    @Test
    public void shouldCallIntentWhenClickedOnCameraClickButton() throws IOException {

        presenter.chooseImage();
        verify(view).galleryImageSelected(captor.capture());
        Intent intent = captor.getValue();
        String action = intent.getAction();
        String type = intent.getType();

        assertThat(action, is(Intent.ACTION_GET_CONTENT));
        assertThat(type, is("image/*"));
    }

}

Now to verify view's method, I have to pass the intent in galleryImageSelected() method, but as intent was a local variable, how do I test this? Do I have to mock the variable intent and then pass, and if yes how to mock an intent variable.

Also if I am doing the following thing:

   @Test
    public void shouldCallIntentWhenClickedOnCameraClickButton() throws IOException {
        presenter.chooseImage();
        Intent intent = new Intent();
        intent.setType("image/*");
        intent.setAction(Intent.ACTION_GET_CONTENT);
        verify(view).galleryImageSelected(intent);
    }

I am getting the following error while testing:

Argument(s) are different! Wanted:
view.galleryImageSelected(null);
-> at com.example.imagepicker.ExampleUnitTest.shouldCallIntentWhenClickedOnCameraClickButton(ExampleUnitTest.java:52)
Actual invocation has different arguments:

Answer 1

You cannot mock local variable but you can capture the argument passed, using ArgumentCaptor and then validate argument as -

@RunWith(MockitoJUnitRunner.class)
public class PresenterTest {

  @Mock
  private View view;
  @InjectMocks
  private Presenter presenter;

  @Captor
  private ArgumentCaptor<Intent> captor;

  @Test
  public void shouldCallIntentWhenClickedOnCameraClickButton() {
    presenter.chooseImage();
    verify(view).galleryImageSelected(captor.capture());
    Intent intent = captor.getValue();
    String action = intent.getAction();
    String type = intent.getType();
    assertThat(action, is(Intent.ACTION_GET_CONTENT));
    assertThat(type, is("image/*"));
  }
}