@Test
public void setBodyWith_noObservers() throws CoapException {

    NotificationDeliveryListener delivListener = mock(NotificationDeliveryListener.class);
    obsResource.setBody("", delivListener);
    verify(delivListener).onNoObservers();
    verify(delivListener, never()).onFail(any(InetSocketAddress.class));
    verify(delivListener, never()).onSuccess(any(InetSocketAddress.class));
}