Candidates have to pass the theory test before being allowed to try the practical test. Basically the Kingdom needs to know you will be safe with a broomstick before letting you near one or to ride it in areas where you will come across the general public. (If you fly in lonely areas and crash, that’s considered your bad luck. Don’t expect sympathy here. That way you can’t be disappointed).
There is no limit to how many tests you can take (though it is considered bad form to go beyond 3 on each. These few unfortunates are generally avoided. It is suspected they are probably accident prone which is why they took so long to pass).
The theory test has two parts to it - a written, multiple choice paper and a hazard perception test. On the face of it this is the same as the Earth based driving system but the hazard perception test is far more difficult in the Fairy Kingdom.
Magic complicates things and creates far more hazards than can be listed here. Candidates are expected to be able to spot and stop 100% of those that are fatal (literally if you fail you die), 80% of the ones likely to cause major injury (nobody spots them all and risking injury in the magical realm is an occupational hazard from everyone from the Fairy Queen downwards) and 75% of the ones likely to set off revenge attacks on you and/or your loved ones. It is so easy to offend a witch here. And it really isn’t worth it.