There are lots of answers here on how to answer to negative questions like "Don't you ...?", e.g. How to answer a negative question without ambiguity?. But I am not sure about answers to a question like this:
Q: You haven't started the tests yet, right?
This was the (non-native speaker's) answer:
A: Yes I haven't started yet.
I wondered if it should not be "No, I haven't started yet" instead. On the other hand, perhaps one could answer "yes" to the "right?" part...