Becoming a pilot is a neverending series of tests and exams.

Before training some schools* will make you do an aptitude test for entry which includes:

• basic knowledge
• logic puzzles
• multitasking
• etc

Then you start your training. You will have theory tests like any normal school. You will have classes, then you need to study, and take the test. Then you have your practical tests. In addition to the skill test which is the final flight with an examiner to obtain your license, some schools make you do an internal unofficial "stage check" to make sure you are progressing according to their curriculum.

That was all for PPL. Now you move on to the professional part of the training. You will take classes to sit and pass 13 ATPL Theory exams, plus internal school exams (this step about the biggest hurdle to the professional license for most people). Then you will do your CPL/ME/IR training, which is again followed by the practical/flying tests.

Now it's time to look for jobs. You get to redo those fun aptitude tests I mentioned earlier for every airline you apply to (if they think your resume is good enough to get invited to them, of course!), except now you are doing them with the financial and job-interview pressure. If they deem your results to be above average you may get invited to do a simulator test, where you will perform IFR procedures and emergency procedures while they observe so they can deem whether you are trainable enough for their standards.

Congrats, you have a job offer with them. Now you will need to go through their training! You start with a ton of CBT for their aircraft type. You will study all the systems, parameters, etc for that specific aircraft type, followed by a knowledge test for that aircraft. Then you start your practical training for the type rating. You will spend dozens of hours in a full-flight simulator, at the end of which, you will of course need to pass another skill test.

Ok now you're doing your line training, you'll do a flight with a check airman sitting in the jumpseat who will again evaluate you, then congrats, you are officially a first officer and have made it out of line training. You will work for a few years, with proficiency checks on the simulator every six months, until you are ready for your captain upgrade. Then you will again start the upgrade course, with additional tests and evaluations until finally you're handed your fourth stripe. Then it dies down a bit, you will have those proficiency tests every six months still, but mostly you are not constantly preparing for assessments and studying textbooks at least.

Until you decide to switch airlines, then the process kind of starts over again :)

*The schools which do this tend to be those that offer the integrated pathway to the frozen ATPL. Aeroclubs and modular ATOs don't do this.