### Question:
ZoomLevelSelectorView extends Composite implements ZoomLevelSelector.View { @EventHandler("decreaseButton") void onDecreaseLevel(ClickEvent event) { presenter.onDecreaseLevel(); }  @Override void init(final ZoomLevelSelector presenter); @Override void add(final String text,
                    final Command onClick); @Override void clear(); void setSelectedValue(String selectedItem); @Override void setText(String text); @Override void setEnabled(boolean enabled); @Override void dropUp(); @PreDestroy void destroy();  }### Answer:
@Test public void testOnDecreaseLevel() { tested.init(presenter); tested.onDecreaseLevel(mock(ClickEvent.class)); verify(presenter, times(1)).onDecreaseLevel(); }