@Test
public void toJsonReturnsExpected() {

    final SendFeatureMessage<?> underTest =
            SendFeatureMessage.of(THING_ID, FEATURE_ID, MESSAGE, TestConstants.EMPTY_DITTO_HEADERS);
    final JsonObject actualJson = underTest.toJson(FieldType.regularOrSpecial());
    assertThat(actualJson).isEqualTo(KNOWN_JSON);
}