@Test
public void tryToGetInstanceWithNullEntityId() {

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