A candidate may face initiation tests to verify if those prerequisites are met. The exam also allows someone to demonstrate how good they really are at a skill. If they’re already advanced, maybe they can skip some training, have a superior trainer, or be singled out for honing into a finer warrior; we can also use this to make peers resent that person. We should decide what weapons are tested and what level of skill is required for each, with some preferred over others.
Tests can also focus on how a candidate reacts to failure or challenges. Someone who whines about unfairness is likely frowned upon. Does a combatant get back up or otherwise shrug off a blow? Some of this is to be expected, but consider if a trait like unusual perseverance is required. Must members of this military stand for a day without fatigue? If so, this might be tested, but development of it might expected during training rather than being there from the start. Imagine ways we’d use this military and its members and then concoct tests to demonstrate potential.
An example of what to write for a knighthood might be: “The minimum requirements are: demonstrated skill with the sword, average proficiency with a horse, average skill with at least one missile weapon, a willing desire to learn weapons skills, and honorable conduct at all times.”