### Question:
BindingManager { public void removeUiUpdateObserver(UiUpdateObserver observer) { requireNonNull(observer, "observer must not be null"); uiUpdateObservers.remove(observer); } BindingManager(ValidationService validationService); @Deprecated BindingContext startNewContext(Class<?> clazz); BindingContext createContext(Class<?> clazz, PropertyBehaviorProvider behaviorProvider); @Deprecated BindingContext startNewContext(String name); BindingContext createContext(String name, PropertyBehaviorProvider behaviorProvider); BindingContext getContext(Class<?> clazz); BindingContext getContext(String name); @Deprecated Optional<BindingContext> getExistingContext(Class<?> clazz); @Deprecated Optional<BindingContext> getExistingContext(String name); @Deprecated BindingContext getExistingContextOrStartNewOne(Class<?> clazz); @Deprecated BindingContext getExistingContextOrStartNewOne(String name); void removeContext(BindingContext context); void removeAllContexts(); void addUiUpdateObserver(UiUpdateObserver observer); void removeUiUpdateObserver(UiUpdateObserver observer); void afterUpdateUi(); void notifyUiUpdateObservers(); @Override String toString();  }### Answer:
@Test public void testRemoveUiUpdateObserver() { TestBindingManager bindingManager = new TestBindingManager(() -> new MessageList()); UiUpdateObserver observer = mock(UiUpdateObserver.class); bindingManager.addUiUpdateObserver(observer); bindingManager.removeUiUpdateObserver(observer); bindingManager.afterUpdateUi(); verify(observer, never()).uiUpdated(); }