Whatever you get on this test mirrors your academic ability. While there are some other facts the principle does not change. If you do bad on this test than clearly you just are super smart. Classwork is too easy honestly and is a bad measure for intellect. IQ is another good way to measure intellect
Standardized testing truly represents a student's capability of taking standardized tests. It may not truly represent what a student's capability of the material covered on the standardized test, but it still truly represents a student's capability of something. And for that reason, the answer to the question is a technically yes.
I believe that a student may not be able to show there full capabilities through a standard test. Many things could possibly affect the outcome of the test, such as things like; temperature, surroundings, peers around them. These would affect the result of the test but not ability. It is hard to display a persons wide range of credentials through a standardized test, because the test will be designed for a variety of people of different abilities. Also I believe that the exam boards design questions to allow people to develop different interpretations, now a student may be incredibly smart but not have the ability to display there interpretations as well as the examiner would like, it is too hard for students of the modern age to fully show there potential. So albeit a student may have incredible capabilities but tests are now designed in such a way that students are not able to express there ability.
Although it is used to see where the student is in intelligence it is not used for most capabilities. Its for capabilities not for whether they are smart or not. Not all of what you learn in school is used in school you could be a garbage man and know nothing.