How to mock Picasso in unit tests in Android?

Question

I have code where Picasso library is used.

 @Inject
 public RegistrationPresenter(UserData userData, Picasso picasso) {
    this.userData = userData;
    this.picasso = picasso;
 }

 @Override
 public void attachView(RegistrationView view) {
    super.attachView(view);
    view.toggleKeyboardButton(false);
    view.showFirstName(userData.getFirstName());
    view.showLastName(userData.getLastName());
    view.showEmail(userData.getEmail());
    setImage();
 }

 private void setImage() {
    String url = String.format(IMAGE_URL, userData.getId());
    String tag = String.format(JPG_EXT, userData.getId());
    picasso
            .load(url)
            .tag(tag)
            .into(new Target() {
                @Override
                public void onBitmapLoaded(Bitmap bitmap, Picasso.LoadedFrom from) {
                    //some actions
                }

                @Override
                public void onBitmapFailed(Drawable errorDrawable) {
                }

                @Override
                public void onPrepareLoad(Drawable placeHolderDrawable) {
                }

            });
}

In my presenter I provide picasso via Dagger2

@Provides
@Singleton
Picasso providesPicasso() {
    return Picasso.with(context);
}

In my tests I'm using Robolectric and Mockito, so I mock Picasso and pass it in presenter's constructor

@Mock
Picasso picasso;

@Before
public void setUp() {
    super.setUp();
    MockitoAnnotations.initMocks(this);
    mockData = new UserData();
    mockData.setFirstName("Name");
    mockData.setLastName("LastName");
    mockData.setEmail("example@gmail.com");
    mockData.setId("123456");

    File mockCacheDir = mock(File.class);
    Context mockAppContext = mock(Context.class);
    when(mockContext.getApplicationContext()).thenReturn(mockAppContext);
    when(mockContext.getApplicationContext().getCacheDir()).thenReturn(mockCacheDir);
    when(view.getContext()).thenReturn(mockContext);
    presenter = new RegistrationPresenter(mockData, picasso);
}

@Test
public void testAttachView() {
    presenter.attachView(view); //fails here
    verify(view).toggleKeyboardButton(false);
    verify(view).showFirstName(mockData.getFirstName());
    verify(view).showLastName(mockData.getLastName());
    verify(view).showEmail(mockData.getEmail());
}

When I run my test, it fails with exception

java.lang.NullPointerException
at com.squareup.picasso.Utils.createDefaultCacheDir(Utils.java:257)
at com.squareup.picasso.OkHttpDownloader.<init>(OkHttpDownloader.java:45)
at com.squareup.picasso.Utils$OkHttpLoaderCreator.create(Utils.java:424)
at com.squareup.picasso.Utils.createDefaultDownloader(Utils.java:250)
at com.squareup.picasso.Picasso$Builder.build(Picasso.java:832)
at com.squareup.picasso.Picasso.with(Picasso.java:662)

What is proper way to mock Picasso?

Could you show us the unit test that fails? Without seeing it I'd suspect that the problem is that you never set any behavior for your `Picasso` mock. Mocks don't use the real methods of the mocked class, so they will just return null by default. — Pox, Feb 02 '17 at 09:36

score 1 · Answer 1 · edited May 23 '17 at 12:24

1

Don't mock File. Most likely your test fails because real File implementation is required. Instead use TemporaryFolder rule:

@Rule
public TemporaryFolder folder = new TemporaryFolder();

@Before
public void setUp() {
  // ...
  when(mockContext.getApplicationContext().getCacheDir()).thenReturn(folder.newFolder()));
  // ...
 }

edited May 23 '17 at 12:24

Community

1
1

answered Feb 02 '17 at 09:38

Mykhailo

1,134
2
17
25

Now it fails with NPE here `picasso .load(url) .tag(tag)` – user2806449 Feb 02 '17 at 10:02
1

Can you create a new Stackoverflow question for the new NPE, please. That makes it easier for everybody to focus on that specific problem. – Stefan Birkner Feb 02 '17 at 10:13

How to mock Picasso in unit tests in Android?

1 Answers1