@Test
public void filterValueWithTwinPersistedOnlyAckRequest() {

    final DittoHeaderDefinition headerDefinition = DittoHeaderDefinition.REQUESTED_ACKS;
    final AcknowledgementRequest twinPersistedAckRequest =
            AcknowledgementRequest.of(DittoAcknowledgementLabel.TWIN_PERSISTED);
    final JsonArray ackRequestsJsonArray = JsonArray.newBuilder().add(twinPersistedAckRequest.toString()).build();
    final DittoAckRequestsFilter underTest = DittoAckRequestsFilter.getInstance();
    assertThat(underTest.apply(headerDefinition.getKey(), ackRequestsJsonArray.toString())).isNull();
}