### Question:
SelectVariablesPresentation extends Model implements SelectFromFiniteListPresentation<T> { public void addSlot() { StudyOutcomeMeasure<T> som = new StudyOutcomeMeasure<T>(d_type); WhenTaken measurmentEpoch = d_wtf.buildDefault(); if(measurmentEpoch != null) { som.getWhenTaken().add(measurmentEpoch); } d_slots.add(som); bindSlot(som); } SelectVariablesPresentation(ObservableList<T> options, Class<T> type, String title, String description, WhenTakenFactory wtf, AddisWindow mainWindow); ObservableList<T> getOptions(); void addSlot(); int countSlots(); void removeSlot(int idx); StudyOutcomeMeasure<T> getSlot(int idx); ValueModel getAddSlotsEnabledModel(); ValueModel getInputCompleteModel(); boolean hasAddOptionDialog(); void showAddOptionDialog(int idx); String getTypeName(); String getTitle(); String getDescription(); List<ModifiableHolder<T>> getSlots(); void setSlots(List<StudyOutcomeMeasure<T>> slots); static final String PROPERTY_NSLOTS; }### Answer:
@Test public void testAddSlot() { assertEquals(0, d_pm.countSlots()); d_pm.addSlot(); assertEquals(1, d_pm.countSlots()); }