To begin with, you don't have to write your own tests, you can just submit.

There's some basic documentation here: https://www.codewars.com/docs/js-slash-coffeescript-test-reference. Also, look how tests are done in the katas you've solved.

10% less than the candidate's minSalary. The job posted a max salary that is below the candidate's minimum accepted salary, but if it turns out to be a good match despite that, it can still be considered.