Think you should define what you think is a junior developer.

Because in my experience seniors/juniors have not that much to do with the type of tasks you do, but more with the responsibilities. I would advise against taking a job that would put you into a QA position because you are a junior. The only way you become better is by actual development, code reviewing working together with other people, writing tests for your code. Reading books like refactoring, clean code/solid, code complete and working effectively with legacy code. While you make mistakes, and learn from it.