Mockitio - returning null when expecting mock in unit test

I have a method in a class called FruitBasket which I would like to test as so:

// Method to test
public Fruit getFruit(String fruitName) {
    Fruit fruit = new Fruit();

    if(fruitExists(fruitName)) {
        fruit = getFruitByName(fruitName);
    }
    else {
        fruit.setFruitName(fruitName);
        saveFruit(fruit);
        fruit = getFruitByName(fruitName);
    }

    return fruit;
}



private Fruit getFruitByName(String fruitName) {
    return fruitDao.getFruitByName(fruitName);
}

public boolean fruitExists(String fruitName) {
    return fruitDao.fruitExists(fruitName);
}

I have written a unit test for this method as follows:

@Mock
FruitDao fruitDao;
@Mock
Fruit mockFruit;

@Before
public void setUp() {
    MockitoAnnotations.initMocks(this);
}

@Test
public void testgetFruitMethod() {
    FruitBasket fruitBasket = new FruitBasket (fruitDao);
    Fruit apple = fruitBasket.getFruit("Apple");

    when(fruitDao.fruitExists(anyString())).thenReturn(true);
    when(fruitDao.getFruitByName(anyString())).thenReturn(mockFruit);

    assertThat(apple, instanceOf(Fruit.class));
}

However the test fails with an assertion error. An instance of Fruit was expected but null was returned instead.

Can anyone spot an issue to why I am getting null?