On the CodeDiesel.com blog today Sameer has posted a quick code snippet that lets you see if a numeric array is already ordered correctly (useful for something like unit testing).

I recently wrote a quick code to find if a numeric array is ordered i.e sorted in a ascending or descending order. I needed it to check a sort algorithm I had written. The problem is that the following code has a worst-case running time of O(N).

He includes the forty-five line function that takes in the array and the sort order it should match. The code then loops around through them checking the value against an incrementing local variable. Also included is an example of its use in a unit test, passing it into an assertEquals for a PHPunit test to check the given array.