Provide a "fixed seed" setting

[DRMacIver]

Verifier supports a configurable random number generator and all use of randomness goes through that.

However if you do not provide one it will just create one with the default seed. It is desirable to run tests in a deterministic mode, which you could do by having Verifier create its random with a fixed seed instead.

In this case it would be better to have the randomisation happening per falsify run rather than be on the Verifier object.

Planned solution is to create the seed as some sort of hash of the hypothesis. e.g. use hypothesis.name or inspect.getsource(hypothesis) if hypothesis is a lambda. This ensures tests cannot interfere with each others' randomness.

[DRMacIver]

Note that you need to be able to easily override this on a per test basis too: Otherwise you can have tests which just by virtue of bad luck will consistently report as unsatisfiable.

[DRMacIver]

Fixed in fb24ab4 and released in 0.3.2