There are two valid forms of personality tests: Myers-Briggs and the Sorting Hat—BUT ONLY the Sorting Hat as defined by the collective wisdom of the broader Harry Potter fandom. J. K. Rowling’s Slytherinphobia is as well-documented as it is inexplicable. Pottermore cannot be trusted.
If you don’t know your Myers-Briggs personality, you can find it out pretty easily. The internet is clogged with free tests of varying length and quality. I like this one, personally. It’s thorough but nowhere near as long as others.
In general, Myers Briggs judges personalities in four metrics: introvert (I) vs extrovert (E), sensing (S) vs intuition (N), thinking (T) vs feeling (F), and judging (J) vs perceiving (P).
If you don’t want to take a quiz, you may be able to guess what you are. Introverts feel recharged when alone, and extroverts feel at-home among others. Sensors like to take people at their word, while intuits tend to look for meaning between the lines. Thinkers are rational and logical, while feelers are empathetic and expressive. Judgers (not to be confused with the judgmental) prefer plans and orderliness over the perceiver’s more casual, open-ended approach.