mockito anyList of a given size
I'm verifying with mockito that a method has been called. The method:
public void createButtons(final List<Button> buttonsConfiguration) {...}
Since It doesn't matter which list is passed I verify that the method is called as follows:
verify(mock).createButtons(Matchers.anyListOf(Button.class));
But, the size of the List
is important. So, it doesn't matter which List
but the list has to have X elements.
Is that possible at all?
One way is to use a Captor
ArgumentCaptor<List> captor = ArgumentCaptor.forClass(List.class);
verify(mock).createButtons(captor.capture());
assertEquals(x, captor.getValue().size()); // if expecting single list
assertEquals(x, captor.getValues().size()); // if expecting multiple lists
See http://docs.mockito.googlecode.com/hg/org/mockito/Mockito.html#15 for the documentation.
You could also use a custom argument matcher. The documentation shows an example that does exactly what you want:
http://docs.mockito.googlecode.com/hg/org/mockito/ArgumentMatcher.html
class IsListOfTwoElements extends ArgumentMatcher<List> {
public boolean matches(Object list) {
return ((List) list).size() == 2;
}
}
List mock = mock(List.class);
when(mock.addAll(argThat(new IsListOfTwoElements()))).thenReturn(true);
mock.addAll(Arrays.asList("one", "two"));
verify(mock).addAll(argThat(new IsListOfTwoElements()));
You could, for instance, also add a constructor so you can specify list size desired, etc.
With Mockito 3.x, and 2.1+ you can use Java 8 lambda expressions:
verify(mock).createButtons(argThat(list -> list.size() == 5));
With Mockito 2.1 and below similar:
verify(mock).createButtons(argThat(list -> ((List) list).size() == 5));
To check emptiness it is even easier:
verify(mock).createButtons(argThat(List::isEmpty));
Hamcrest (hamcrest-library dependency) provides a simpler way.
verify(mock).addAll((List) argThat(IsCollectionWithSize.hasSize(4)));
or with static import org.hamcrest.collection.IsCollectionWithSize;
verify(mock).addAll((List) argThat(hasSize(4)));
Here is the working example for me:
List<Object> objects = mock(List.class);
when(objects.size()).thenReturn(1000);