Conjecture is a new approach to property based testing.

The core concept of Conjecture is: What if you could do the most basic sort of randomized testing which everybody starts out with, only instead of it being awful it was actually amazing?

Classic property based testing has a strict separation between example generation and testing, which makes it very hard to use for tests that don't easily match that discipline. Suppose I want to do some calculation and then pick a random element of the result. How do I do that?

In Conjecture, instead of having distinct concepts of example generation and tests, everything is a test and everything can generate examples. Testing is a simple matter of writing functions which take a type of random number generator but whose output is under Conjecture's control and can be controlled to produce interesting behaviour and then simplified to produce the minimal possible behaviour.

The result is a style of testing that is more natural to use, easier to implement, and yet strictly more powerful than classic Quickcheck style property based testing.

If you want to know more about how it works, there is a rough design doc also checked in to this repo.

If you want to see some examples of usage, there's a collection of simple tests (most or all of which fail) in the repo demonstrating some common behaviours and approaches.

Conjecture is very young and doesn't really have a community of its own, but discussion of it is extremely welcome in the Hypothesis Community.

In particular we have the IRC channel #hypothesis on Freenode.

Please note that there is a code of conduct in effect in this community and you are expected to adhere to it.

Conjecture is currently a prototype. The python code base demonstrates that it works (extremely well in fact) but is not ready to use, and besides you should probaby be using Hypothesis instead.

If you're interested in having Conjecture available for your language, I am able and willing to do so for a very reasonable day rate: The design is one that is extremely easy to port to new languages, so in most cases it is unlikely to take more than a month of work to get a solid version available.

All versions of Conjecture are / will be licensed under the GPL v3. If you wish to use it under a different license, please contact me at licensing@drmaciver.com.