I was invited to the office to be interviewed by the art director and two or three designers. Everyone was pretty laid back and friendly; it was a very low-anxiety experience. We went over my portfolio, and then they showed me examples of the ad units they made as well as info about the company.
I can understand why people might be thrown off by the art test. I certainly was surprised at the time. This is typically something that people who work in the animation industry have to deal with, but not so much in graphic or motion design. However, the design team knew this and told me to take my time with it and not go crazy. Overall, it was pretty easy and I thought it was an effective way to prove myself, even if I wasn't terribly excited about doing it.
I work here now, but please don't think I'm writing this just to make my company look better. No one has asked me to write this. I simply don't enjoy seeing false accusations from other reviewers being marked as "helpful." And I want potential candidates to know the truth.
They are not stealing your art test and using it as free work.
They encourage you to use Google Images to find whatever assets you need––that's not how real ads are made, that's how spec ads are made. Almost all of the art tests come back as videos––why would a company spend the time to mimic a video of an advertisement, one that takes candidates up to a week to build, and completely rebuild it in HTML5? We make ads like the one in the test all the time, and can do it much quicker.