Efficient Hypothesis strategies

[Zac-HD]

This pull request fixes #404, which I opened a few years ago to fix some performance issues related to your rejection sampling, prompted by this stackoverflow question.

Recent Hypothesis versions can usually rewrite filters expressed as partial(operator.xxx, bound), and so this style is considerably more efficient in most cases. The only downside is that it can take a few minutes to get used to the partial() calls being "backwards", so lambda x: x < y becomes partial(op.gt, y) (via lambda x: y > x).

In the process, I also fixed two regex-related bugs where you'd see different behavior between the first and subsequent filters:

• str_matches_strategy used fullmatch for the first, but match for subsequent filters, allowing generation of data with a disallowed suffix
• for the first filter, str_startswith_strategy and str_endswith_strategy prepended/appended a regex boundary to the pattern. However, if the pattern includes alternation (e.g. a|b), this boundary would only be applied to the first/last branch, and thus invalid data could be generated. Placing the user's pattern inside a group resolves this problem.

Finally, I've updated the minimum Hypothesis version to that required for efficient length filtering, and included some regex expressions where the corresponding Hypothesis issue is currently open - so that they'll become efficient for your users as soon as we ship that.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.29%. Comparing base (4df61da) to head (3df43d4).
Report is 15 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1503   +/-   ##
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  Coverage   94.29%   94.29%           
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  Files          91       91           
  Lines        7024     7029    +5     
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+ Hits         6623     6628    +5     
  Misses        401      401           

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[cosmicBboy]

Thanks @Zac-HD !

[Zac-HD]

Woohoo! I wonder if we'll get user reports of their tests suddenly working much faster 😁