Walmart Software Engineer interview questions

This interview was through the career fair. I went on time for the interview and after waiting for an hour, finally it was my turn. There was only one question that was asked. It was regarding TDD. I answered all the questions that was shot at me. And the interviewer seemed really convinced. He told me I'd be hearing from them for next rounds or so soon. After a week I got a rejection email from them.

I dropped the resume at the career fair, and they scheduled an interview next day. They reviewed the resume and asked about the project. Then they asked brain teaser puzzles. They said I would have online test and then on-site.