If you simply follow drills and deliberate patterns, there is no way to gauge what will emerge in reality. Random attacks - incorporating a variety of punches, kicks and grapples - test your ability to respond spontaneously.
The exercise should be playful and fun, but the attacker must strike with the intention of making contact.
Afterwards, you look at areas of weakness and doubt. Focus upon the gaps and deficiencies: consider what you did wrong, why it didn't work and what you need to do in order to improve your response. Your partner should help you with this, along with your teacher (if required).