Browse the tests, select one, run it and find out how good you are.
If you have top skills, you deserve to get paid more. Learn new things and boost your confidence. Then negotiate higher sallary.
Create your own selection of questions. Save it as test and use it for practicing. You can simulate job interview every day.
Keep your knowledge up-to-date and work on the details. Become the most valued team member with all the advantages and perks.