The term "test" is derived from the root word "testicle", because it is a ball-busting challenge for students. The mere thought about taking a test induces feelings of stress and anxiety which can weaken the immune system and lead to serious illness and even suicide. Teachers know this and use tests as a subtle, yet sadistic, form of torture. Some days when they are in a good mood they will call the test a more merciful sounding name like quiz. But on days when they are in a bad mood they call the test an exam. The final exam is the grand daddy of all tests, and when that day comes it is judgment day for students.
The way most tests are designed requires students to memorize a mass amount of frivolous trivia and useless technical gobbledygook, which has no purpose other than to make teachers seem smarter so that students feel dumber. The problem with that type of test is that some students can be a general dunce, yet very skilled at memorizing data. While other students can be a general super-genius, but not very good at memorizing irrelevant information.
Education is all one big test subdivided into an infinite series of smaller mini-tests. As far as students are concerned everything is a test, starting with their first IQ and monitoring their attendance record, even their basic attitude toward education is evaluated like a test. Everything about the student is examined and graded. Male students test the manliness of their peers by measuring the size of their penises. With girls it's their breast measurements.
Even though tests are not the least bit scientific or in any way professional, students are wrongly judged and punished based on the biased whims of the tester. Student awareness of this teacher tyranny has lead to wide spread practice of cheating on tests. Education has become a contest between the unjust powers of the teachers' tests versus the students' prowess at countermanding that by cheating. It's a natural byproduct of the competitive culture of schools - in other words just another sport. Successful cheating is rewarded with a passing grade and unsuccessful cheating is punished with a failing grade, or administrative discipline.
So students have the incentive to always cheat successfully. Whenever a dumb student makes a high score on a test some teachers suspect them of cheating and gives them a failing grade - whether or not they actually cheated. The strongest motivation that some students have for cheating is to avoid the wrath of their parents. Some parents react to a failing grade by denying their child treats, others react by beating the kid with a belt.
There are many types of tests and even many more types of cheating. Tests are tightly controlled and classrooms are strictly monitored, allowing little room for a chance to pull a fast one. So cheating encourages creative conniving and illicit innovation - important skills that are so necessary in the white collar crime job market, which is where the money is.