When a witness is cross-examined, he may, in addition to the questions hereinbefore referred to be asked any questions which tend-
(1) to test his veracity.
(2) to discover who he is and what is his position in life, or
(3) to shake his credit, by injuring his character, although the answer to such questions might tend directly or indirectly to criminate him or might expose or tend directly or indirectly expose him to a penalty or forfeiture.
