@Test
public void tryToGetInstanceWithNullAcknowledgementLabel() {

    assertThatNullPointerException()
            .isThrownBy(
                    () -> ImmutableAcknowledgement.of(null, KNOWN_ENTITY_ID, KNOWN_STATUS_CODE, dittoHeaders, null))
            .withMessage("The label must not be null!")
            .withNoCause();
}