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