There are four stages typically in the Guidewire Interview process for a QA Engineer, they are:
Phone Screen:
This is where a recruiter from Guidewire phones you to ask about your experience, interest in the job and knowledge of the company.
Exam:
Once passed the phone screen you will sit an exam, you'll have a day or two to complete it and the questions on it range from testing, problem solving and software engineering.
Phone Interview:
Once passed the exam, you will have an interview with an employee of the company, sometimes someone who'll be on your team of the same (if not higher) position as you. The questions asked for this part revolves around types of testing, testing criteria, automation knowledge and further software engineering questions. *cough* databases *cough*
1:1 Back-to-back Interviews:
Once you pass the phone interview, the recruiter will schedule three interviews, one with your manager, one with another QA Engineer on your team, and a random software engineer from any team.
Further Readings:
If you're still reading this, please don't fret the interviewers are there to help you throughout the process, if you don't know how to answer a question don't get annoyed, just ask the interviewer for more details, and if you really don't know the answer then tell the interview to give you examples.
Don't worry if your nervous, most people are so it's normal. When I was taking these interviews I was very nervous especially the final ones, but make sure you know what your talking about and you'll fly by to success!