There is a lot of talk on HN about the best way to do IT recruitment, but whatever method is close it really shouldn't take more than a few hours of face-to-face contact and some legitimate tests. With HR doing due diligence by checking references etc after an offer is made.
The first time I encountered this I was told that I would have to do a 8-12 hour coding challenger over the weekend. They wanted me to come up with a way of proving someone has watched a training video without skipping or faking an API call - something they admitted in their interview that their system was lacking i.e. free work for them. I told the recruiter that I would not be doing any such thing. I have young children and my weekend time is precious. If you can't validate my skills from my a few interviews, my detailed CV, plus HR doing due-diligence, then it makes me wonder about the organisational culture of your company.