Smile because you know it's a test, you're confident, you aren't scared, you welcome the test.
Remember back in school, huge exam at the end of the year, you weren't prepared, the look on your face, one of horror.
Remember another time that you studied your a$$ off and when the exam was in front of you, you smiled, because the test was easy, it was like you had the textbook inside your head, you "aced" it.
Confidence, it's a good thing to have, worthy of a smile, it also tells your spouse that you're ready for her and her tests - they expect you to be thrown off by the tests, they have to, otherwise why test you? They don't expect you to be ready for the tests, you're one of the few people she'll confront that is ready for the tests. The tests exist for a reason, to test how you handle them.
