### Question:
StackRegistry implements DynamicRegistry<T> { @Override public boolean isEmpty() { return items.isEmpty(); } StackRegistry(final KeyProvider<T> keyProvider,
                         final Stack<T> items); T peek(); T pop(); @Override void register(final T item); boolean remove(final T item); @Override boolean contains(final T item); @Override boolean isEmpty(); T getItemByKey(final String id); int indexOf(final T item);  }### Answer:
@Test public void testEmpty() { when(stack.isEmpty()).thenReturn(true); boolean empty = tested.isEmpty(); assertTrue(empty); }
@Test public void testNotEmpty() { when(stack.isEmpty()).thenReturn(false); boolean empty = tested.isEmpty(); assertFalse(empty); }