             //given
             _sut.filterFunction = allowAll;
             _sut.refresh();
+            const positionOfFirstWorkout:int = _sut.getItemIndex(_firstWorkout);
 
             _noTimesFilterFunctionCalled = 0;
             _lastFilteredObject = null;

            //then - no fatal, and object has been filtered
            assertEquals(1, _noTimesFilterFunctionCalled);
            assertEquals(_firstWorkout, _lastFilteredObject);
        }

        [Test]

            //then
            assertTrue(positionOfNull != -1);
            assertEquals(-1, _sut.getItemIndex(null));
            assertEquals(positionOfFirstWorkout, _sut.getItemIndex(_firstWorkout));
        }

        [Test]
