spaniard89 / Codility-PHP-Q2

I recently took a codility test and decided to make some repos based on the questions as an opportunity show some of my coding abilities in PHP. This solution shows how to programatically create the following function and has supporting PHPUnit tests. P(0) = 1. P(N) = (A * P(N−1)) mod B if N > 0. For example, if A = 4 and B = 9 then P(0) = 1, P(1) = 4, P(2) = 7, P(3) = 1, etc.