What it means

I hear "is up to you" when I ask about... anything.
Is there specific content?
A set calendar?
Specific objectives?
Is up to you. But you give test tomorrow, okay?
Test on what?
Is up to you.
What should be on it? What should the students study?
Is up to you.
How long should it be? What type of questions?
Is up to you.

You have test to show me?
Here.
Why is not F4 paper?
Should be multiple choice. Yes, all multiple choice.
Why is so short? 50 questions at least.
Why is not in frame, like this?
Should have school name, class level, semester, number of questions, time on top of frame, and all be multiple choice. See?
Make 55, enough for one class, and give one for me. I make for you answer sheet, and students write on that.

Turns out, there is an extremely specific format and conduct, and a scantron-esque bubblesheet with which every Thai person is familiar. Content of the test is up to you. It just has to look like every other test you've ever taken in Thai school.
Erm....