### Question:
CalendarButtonSelectionAdapter implements GriffonPivotAdapter, org.apache.pivot.wtk.CalendarButtonSelectionListener { public void selectedDateChanged(org.apache.pivot.wtk.CalendarButton arg0, org.apache.pivot.util.CalendarDate arg1) { if (selectedDateChanged != null) { selectedDateChanged.call(arg0, arg1); } }  CallableWithArgs<Void> getSelectedDateChanged(); void setSelectedDateChanged(CallableWithArgs<Void> selectedDateChanged); void selectedDateChanged(org.apache.pivot.wtk.CalendarButton arg0, org.apache.pivot.util.CalendarDate arg1);  }### Answer:
@Test public void testSelectedDateChanged() { final boolean[] invoked = new boolean[1]; CallableWithArgs<Void> callable = new CallableWithArgs<Void>() { public Void call(Object... args) { invoked[0] = true; return null; } }; assertNull(adapter.getSelectedDateChanged()); adapter.selectedDateChanged(null, null); assertFalse(invoked[0]); adapter.setSelectedDateChanged(callable); adapter.selectedDateChanged(null, null); assertTrue(invoked[0]); }