I submitted my application online and then almost immediately received an answer saying I was a promising candidate. They then wanted me to do a "skills test", even though ample evidence of my skills already exist online. The test took almost 48 hours of preparation and of course it was unpaid. I submitted it, only to receive an email 2 months later saying that I did not pass the first round.
I didn't really think it was fair to test someone on a random exercise and then send them a form response. It was a total waste of time, in my opinion. Especially because it was not even realistic (eg, in the real job, you would get more direction and feedback, thus enabling you to completely it correctly).