There are online services such as IKM that offer skills tests in many areas, including programming.Would you use these kind of tests when hiring for a senior developer position?What about just for objectively benchmarking candidates before calling them for an interview? Would you use it as a step after short-listing candidates after interviews?Is this approach more suitable in some situations compared to others? Have you personally used this kind of service or know someone who has?
Will You Use an Online Technical Skills Test to Hire a Senior Developer?
hiring;interview
To be blunt:  No, No, No, No and No!Get the candidate in to do some coding with you, it's the only way you'll know how they think their way through problems and how they might fit into your team.As an aside I'd try to avoid recruiting via the CV lottery technique :-), instead find good people through word of mouth, conferences, technical community meetups etc.  Avoids the sharky recruitment agents as well.