I am afraid not to know anything during a test, or to have a black-out
If you have ever experienced a black-out, it would be a good reason to predict: "I am afraid I will have a black-out." However beware of self-fulfilling prophecies. Let's look at the situation more closely. You have experienced such a situation once or several times previously. Did it influence the result of your test negatively?
Did a black-out influence the result of your test negatively? yes no