I did it years ago. It was just like a casual interview. I was called into a room with a English-majored expert who talked with me about a few casual things and asked me about a few teaching-related questions. And that's it.

But I know some schools did it more formally, like recording your answers and using machines to analyze your annotation and accent, etc.

Bless mm, you'll pass!

 I did in U of Oregon. It is like simple English test on computer. It includes listening comprehension, reading, and writing.
Most of the new students could not pass it, but it is not a big deal. if you could not pass, you need to take English class for one semester. that's it!

good luck!

This kind of test really depends on the university. So the lz mm needs to check with the office in charge of oral test about the format and their expectation. The one in our Univ. is a very formal class with assigned topic. The judges are professors and students with different backgrounds and will ask all kind of weird questions. Language is important, but they care more about the interaction between the TA and students and how TA can respond to any unexpected question. Basically, you should lead the class rather than be led by questions from students. If you don't know the answer or cannot understand their questions, just be frank rather than guessing.

谢谢大家，感激不尽呀，不过还是有点紧张