ProviderTestCase2.getProvider() is null

Question

I'm trying to test a ContentProvider class, and can't make it work.

getProvider() keeps returning null, but as I understand from the ProviderTestCase2.setUp() code, it shouldn't.

public class NotesProviderTest extends ProviderTestCase2<NotesProvider>
{
    ...

    public NotesProviderTest()
    {
        super(NotesProvider.class, Contract.AUTHORITY);
    }

    @Override
    protected void setUp() throws Exception
    {
        super.setUp();

    }

    public void testNoteProvider__inserts_a_valid_record() throws Exception
    {
        Note note = new Note(new JSONObject(simpleNoteJson));

        NotesProvider provider = getProvider();

        Uri insert = provider.insert(Note.URI, note.getContentValues());
        assertEquals(1L, ContentUris.parseId(insert));

        Cursor cursor = provider.query(Note.URI, null, null, new String[]{}, null);

        assertNotNull(cursor);

        cursor.close();
    }
}

Side note: the provider works if used within the app.

Thanks in advance.

Answer 1

I just ran into this issue myself. You need to tell AndroidJUnit4 to run the setUp method with the @Before annotation. If you don't do this the setUp method will not be called before your unit test runs.

The code snippet for overriding the setUp method on http://developer.android.com/training/testing/integration-testing/content-provider-testing.html is misleading and doesn't mention that you need an @Before annotation.

Try the following:

@Before
@Override
public void setUp() throws Exception
{
    setContext(InstrumentationRegistry.getTargetContext());
    super.setUp();
}

Answer 2

As part of the setUp() method a MockContentResolver should be created. Use this to create and inject the provider.

See class MockContentResolver: http://developer.android.com/reference/android/test/mock/MockContentProvider.html

Source of example: http://alvinalexander.com/java/jwarehouse/android/test-runner/src/android/test/ProviderTestCase2.java.shtml

Partial sample from example in link above:

 @Override
    protected void setUp() throws Exception {
        super.setUp();

        mResolver = new MockContentResolver();
        final String filenamePrefix = "test.";
        RenamingDelegatingContext targetContextWrapper = new RenamingDelegatingContext(
                new MockContext2(), // The context that most methods are delegated to
                getContext(), // The context that file methods are delegated to
                filenamePrefix);
        mProviderContext = new IsolatedContext(mResolver, targetContextWrapper);

        mProvider = mProviderClass.newInstance();
        mProvider.attachInfo(mProviderContext, null);
        assertNotNull(mProvider);
        mResolver.addProvider(mProviderAuthority, getProvider());
    }