### Question:
MenuSessionImpl implements MenuSession { @Override public void sendHeader(Map<String, Object> headers) { headerConsumer.accept(headers); } protected  MenuSessionImpl(MenuTemplate menuTemplate, MenuOpenProcessor openProcessor, Player owner, Consumer<Map<String, Object>> headerConsumer); @Override Optional<MenuItem> getItemByIndex(int index); @Override MenuTemplate getTemplate(); @Override Player getOwner(); @Override boolean isOpeningFinished(); @Override void close(); @Override void sendHeader(Map<String, Object> headers); @Override Inventory getInventory(); @Nonnull @Override Consumer<Map<String, Object>> getHeaderConsumer(); @Override void updateItems(); @Override void updateItem(int index); @Override void updateTemplate(MenuTemplate menuTemplate); @Override void setHeaderConsumer(@Nonnull Consumer<Map<String, Object>> consumer);  }### Answer:
@Test public void sendHeader() { Map<String, Object> data = new HashMap<>(); session.sendHeader(data); verify(headerConsumer, times(1)).accept(data); }