DefaultImageIconService implements ImageIconService { @Override @Nullable public Icon getIconForId(@Nonnull final IconID id) { return MAP.get(id); } DefaultImageIconService(); @Override @Nullable Icon getIconForId(@Nonnull final IconID id);  }
@Test public void testAllIcons() { final ImageIconService service = new DefaultImageIconService(); for (final IconID i : IconID.values()) { assertNotNull(i.name(), service.getIconForId(i)); } }