anchor.diff:      2 = nksip_dialog:meta(invite_session_expires, Dialog1A),
       undefined = nksip_dialog:meta(invite_refresh, Dialog1A),
       2 = nksip_dialog:meta(invite_session_expires, Dialog1B),
  -    true = is_integer(nksip_dialog:meta(invite_refresh), Dialog1B),
  +    true = erlang:is_integer(nksip_dialog:meta(invite_refresh), Dialog1B),
   
       % Now both ua1 and ua2 has received a 422 response or a refresh request with MinSE,
       % so it will be used in new requests
  
positive.code:     timer:sleep(100),
      Dialog4B = nksip_dialog:remote_id(Dialog4A, ua3),
      1800 = nksip_dialog:meta(invite_session_expires, Dialog4A),
      true = is_integer(nksip_dialog:meta(invite_refresh), Dialog4A),
      undefined = nksip_dialog:meta(invite_session_expires, Dialog4B),
      undefined  = nksip_dialog:meta(invite_refresh, Dialog4B),
      1800 = nksip_dialog:meta(invite_session_expires, Dialog4A),
  
negative.code:     3 = nksip_dialog:meta(invite_session_expires, Dialog1A),
      undefined = nksip_dialog:meta(invite_refresh, Dialog1A),
      3 = nksip_dialog:meta(invite_session_expires, Dialog1B),
      true = erlang:is_integer(nksip_dialog:meta(invite_refresh), Dialog1B),
  
      3 = nksip_dialog:meta(invite_session_expires, Dialog1A),
      undefined = nksip_dialog:meta(invite_refresh, Dialog1A),
  