You are taking a coding test because the recruiter cannot evaluate you based on a conversation. Even if they were talented enough to be able to, they are not trusted enough by boss / client. The money they make is so good for recruiting a person, it drives a lot of people to push for people who cannot do the job, just for the commission.
<Story Time> A few years back I was looking for work without much luck. Finally I get a call from a head hunter that wanted to place me in a contract. It was short duration, only a month, but as much OT as I wanted. Pay was also very good. They wanted a DB guy. Although I am mostly coder, I do love DB and am more talented at DB than you typical coder. Digging deeper I found out they wanted someone to work at hardening (defense) the DB from intruders. Well that was well outside of my skill set. I refused to take the job as I knew the actual customer would not be happy, and I did not want a reputation for claiming to do stuff I was not capable of.
<Story Time> A few years back I was looking for work without much luck. Finally I get a call from a head hunter that wanted to place me in a contract. It was short duration, only a month, but as much OT as I wanted. Pay was also very good. They wanted a DB guy. Although I am mostly coder, I do love DB and am more talented at DB than you typical coder. Digging deeper I found out they wanted someone to work at hardening (defense) the DB from intruders. Well that was well outside of my skill set. I refused to take the job as I knew the actual customer would not be happy, and I did not want a reputation for claiming to do stuff I was not capable of.