I applied through my university, and interviews were held on campus after a career fair. The first interview was a 30 minute conversation and test with a senior software engineer at Athena, and the second was on-site.

I was invited for the second round, but it was cancelled because they had filled their team for the coming year.

Simple white-boarding exercise, mainly to test logic and thinking abilities. It was not too difficult, coming from an engineering background with a minor in computer science.