In various more functional based languages there are tools (like [Quickcheck](http://en.wikipedia.org/wiki/QuickCheck)) which allow for [property based testing](http://blog.jessitron.com/2013/04/property-based-testing-what-is-it.html).

How would I go about property based testing in PHP?

I would like to be able to specify the in and output properties of a PHP method, and run coverage tests.