They had me complete a sample writing assignment and had me take a very easy computer skills assessment and a very tough IQ-like test (verbal, spatial, and math). The IQ-like test was timed, so be ready to completely focus on that for the alloted time with no interruptions. After that, they emailed me to offer me the position and set up an orientation phone call (that was not an interview, I was already selected, it was just explaining how the job works, the expectations, and how to use their project management system.)
I've seen a lot of people on here speculate that they use the sample writing of not-selected candidates in the test preparation guides, but I can assure you from having worked there for a while since the interview that this is not the case-- I have worked for other companies that did steal people's work during the interview process--and nothing like that is happening here, thankfully.
I'll put a review of what it's like working as a contractor in the employer reviews section.