Add tests for reasoncode comparison

[PierreF]

ReasonCodes object could be compared to a number but they couldn't:

• be used in inequality with number like in reason_code > 0
• be used in equality with string (because code was broken, it's was intended to work), like in reason_code == "Success"

The string comparison if useful IMO. The inequality is there more for compatibility with code that used to do rc > 0 and want to do reason_code > 0.