To dream about an exam, means you are afraid that you may not be up for the challenge or that you cannot meet the expectations of others.

To dream that you miss or late for a test, indicates that you are feeling unprepared for particular situation. It may also reflect your anxiety about a real-life exam.

If you think the exam is difficult, then you will be confronted with unfamiliar problems in your waking life, which you do not know how to approach and resolve.