Calm down fuzzing

[UniversalSuperBox]

The fuzzing configuration introduced by #191 did find a novel issue in its first run. However, it is unable to run on travis-ci due to taking too long without output. I tried running it locally to make sure it wasn't Travis being Travis, and sure enough, on my i9-9880H, the operation took well over 20 minutes before I stopped it.

Because of this, I've reduced the number of examples that Hypothesis will run. This will catch fewer errors but help us get PRs back on track.

Ping @untitaker, who introduced this change originally

[mister-roboto]

@UniversalSuperBox thanks for creating this Pull Request and help improve Plone!

To ensure that these changes do not break other parts of Plone, the Plone test suite matrix needs to pass.

Whenever you feel that the pull request is ready to be tested, either start all jenkins jobs pull requests by yourself, or simply add a comment in this pull request stating:

@jenkins-plone-org please run jobs

With this simple comment all the jobs will be started automatically.

Happy hacking!

[untitaker]

@UniversalSuperBox you might want to look into the deadline parameter instead of max_examples but either way this seems fine

[UniversalSuperBox]

It appears that deadline is for individual examples rather than the entire test case.

[wbob]

On a tangent: Hypothesis allows to use profiles, as @untitaker uses in vdirsyncer. Travis can then be instructed to use a smaller example size, while per default outside CI more samples are generated.
When I stumbled on this issue, I even went down to max_examples=10**3 and set suppress_health_check to avert a failing test[1] as of slow generation (see HypothesisWorks/hypothesis#2009 for a similar case).

[1]: src/icalendar/tests/hypothesis/test_fuzzing.py:24: FailedHealthCheck FailedHealthCheck: Data generation is extremely slow: Only produced 7 valid examples in 1.25 seconds (0 invalid ones and 0 exceeded maximum size). Try decreasing size of the data you're generating (with e.g.max_size or max_leaves parameters).