### Question:
NotificationsEditorWidget extends Composite implements HasValue<NotificationTypeListValue> { void showNotificationsDialog() { notificationWidget.setValue(notificationTypeListValue.getValues() .stream() .map(NotificationRow::new) .collect(Collectors.toList()), true); notificationWidget.setCallback(data -> setValue(data, true)); notificationWidget.show(); }  @PostConstruct void init(); @Override void setValue(NotificationTypeListValue value, boolean fireEvents); @Override NotificationTypeListValue getValue(); @Override void setValue(NotificationTypeListValue value); @Override HandlerRegistration addValueChangeHandler(ValueChangeHandler<NotificationTypeListValue> handler); void setReadOnly(final boolean readOnly);  }### Answer:
@Test public void testShowNotificationsDialog() { values.setValues(new ArrayList<>()); notificationsEditorWidget.setValue(values); setFieldValue(notificationWidget, "view", notificationWidgetViewImpl); setFieldValue(notificationsEditorWidget, "notificationWidget", notificationWidget); notificationsEditorWidget.showNotificationsDialog(); verify(notificationWidget, times(1)).show(); }