The following is the release announcement I sent to the testing in python mailing list and the main python mailing list:

Hypothesis is a Python library for turning unit tests into generative tests,
covering a far wider range of cases than you can manually. Rather than just
testing for the things you already know about, Hypothesis goes out and
actively hunts for bugs in your code. It usually finds them, and when it
does it gives you simple and easy to read examples to demonstrate.

Hypothesis is based on Quickcheck (
https://wiki.haskell.org/Introduction_to_QuickCheck2) but is designed to
have a naturally Pythonic API and integrate well with Python testing
libraries.

It’s easy to use, extremely solid, and probably more devious than you
are at finding
edge cases.

The 1.0 release of Hypothesis has a stable and well documented public API.
It’s more than ready for you to use and it’s easy to get started.

Full documentation is available at
http://hypothesis.readthedocs.org/en/latest/, or if you prefer you can skip
straight to the quick start guide:
http://hypothesis.readthedocs.org/en/latest/quickstart.html

It seems to be a hit – less on the mailing list, but the link to it is doing the rounds of the internet and has the dubious honour of being the first time in ages I’ve been on the front page of Hacker News.