El derecho constitucional costarricense a no declarar como testigo

our constitution on its article number 36 regulates the cases in wich the citizens can -legally- abstain form testifying. it is taken by the common legislation, even though it is not clear the way they regulate the relationship of the author with its pupil. the question comes up with the free union relationship. if it is considerate by the constitutional law as not programatical, the situation is not regulated; practical order reasons comfirm it. the principle "in dubio pro libertates" is not aplly to the free union. therefore, to form part of the legal exceptions to testify, there must be a modification to the constitution.