@Test
public void givenThreeItemWhenSelectAllThenAllSelected() throws Exception {

    // Given
    int expectedCount = 3;
    when(mMockItemList.size()).thenReturn(expectedCount);
    HashSet<Integer> value = new HashSet<>();
    value.add(0);
    value.add(1);
    value.add(2);
    when(mMockItemList.keySet()).thenReturn(value);
    // When
    mMultiChoiceAdapter.selectAll();
    // Then
    verify(mMockItemList, times(expectedCount)).put(anyInt(), eq(MultiChoiceAdapter.State.ACTIVE));
}