You had to build a client library in Go for one of their API resources. The API request objects were large, with at least 20 attributes all with differing business requirements so takes a long time to model. They give you a few do's and do not's, but very little as to the task requirements.
Sigiloso
I spent 8 hours on my solution over 3 evenings. I felt I put in all the fundamental boilerplate code in that time. Could have easily spent 4 times as long as there was so much you could add for this task. In the end I failed simply as I needed to put more time in. Annoying really as I did not fail for anything major, just didn't spend enough time.