@Test
void putStreamer() {

    final String label = "lang";
    final JsonEncoder<Language> other = new JsonEncoderImpl<>(project, languageManager);
    other.put(Language.NAME);
    instance.putStreamer(label, u -> Stream.of(language), other);
    instance.put(User.NAME);
    assertContainsWhenRendered(NAME, LANGUAGE_NAME, label);
}