I was referred by a staffing agency and was told there would be a test of my writing skills. The interview was professionally done, and the interview questions were pretty much what you would expect. Still, I had a hard time connecting with the interviewer, so there was a certain discomfort throughout the process.
The written test consisted of about three parts. The first part consisted of a number of basic grammar and punctuation questions such as how to abbreviate US. In the second part you were given snippets of technical writing and asked to rewrite it. The final part was an essay about what makes you a good technical writer, or something to that effect.
I didn't get a follow up, so it's hard for me to comment on the culture of the place. I can only say that the feeling I got was that it was a pretty formal place to work.