I am afraid not to know anything during a test, or to have a black-out
A "black-out" is unsually a strong combination of
  1. Experiencing sudden strong physical stress
  2. Temporarily not knowing something
It is an unpleasant situation, but all is not lost certainly. The way in which you cope with this largely detemines the outcome of it.
Have you ever experienced such a black-out?

  • yes.

  • no.