QuickCheck-like in Phobos?

[bearophile]

Is it useful to add QuickCheck-like functionality to the Phobos module that helps testing (or is it better to keep it as an module external to Phobos)? It's a nice thing, and it's probably small:
http://en.wikipedia.org/wiki/QuickCheck

At the bottom of that Wikipedia page there are links to the Scala and C++ versions, plus the original Haskell version.

The Python std lib has two different testing modules, but I presume Phobos is not meant to grow as much as the Python standard library.

I vaguely remember a QuickCheck-like module for D (probably D1) already written by someone, but I don't remember the link.

Bye,
bearophile