### Question:
DefaultEventManager implements EventManager { @Override public void unregisterAll() { this.registeredListeners.clear(); }  @Nullable @Override T callEvent(@NotNull Class<? extends T> event); @NotNull @Override T callEvent(@NotNull T event); @NotNull @Override Task<T> callEventAsync(@NotNull Class<? extends T> event); @NotNull @Override Task<T> callEventAsync(@NotNull T event); @Override void registerListener(@NotNull Object listener); @Override void registerListener(@NotNull Class<?> listener); @Override void unregisterListener(@NotNull Object listener); @Override void unregisterAll(); @NotNull @Override @UnmodifiableView List<ListenerContainer> getListeners();  }### Answer:
@Test @Order(7) void unregisterAll() { this.eventManager.unregisterAll(); Assertions.assertEquals(0, this.eventManager.getListeners().size()); }