@Test
public void send413_when_RequestEntityTooLarge_whileHandlingRequest() {

    server.addRequestHandler("/err", exchange -> {
        throw new CoapRequestEntityTooLarge(100, "too big");
    });
    server.coapRequestHandler.handleRequest(newCoapPacket(LOCAL_1_5683).mid(1).con().post().uriPath("/err").build(), TransportContext.NULL);
    assertSendResponse(newCoapPacket(LOCAL_1_5683).mid(1).size1(100).ack(Code.C413_REQUEST_ENTITY_TOO_LARGE).payload("too big"));
}