Took a 1.5 hour test, then was called back for a second interview. On the second interview, was asked to write a science article (which would take two weeks, with no pay). Once I submitted this, I was then asked to do more revisions (for free) before they could move on with the application process. At this point I refused, saying I was being asked to do too much for free. Please be hesitant that the company does not try to get a free article from you.