Add docs and release note

hypothesis-python/RELEASE.rst

@@ -0,0 +1,6 @@
+RELEASE_TYPE: minor
+
+This release adds a new mechanism to infer strategies for classes
+defined using :pypi:`attrs`, based on the the type, converter, or
+validator of each attribute. This inference is now built in to
+:func:`~hypothesis.strategies.builds` and :func:`~hypothesis.strategies.from_type`.

hypothesis-python/docs/conf.py

@@ -71,6 +71,7 @@
  'pandas': ('https://pandas.pydata.org/pandas-docs/stable/', None),
  'pytest': ('https://docs.pytest.org/en/stable/', None),
  'django': ('https://django.readthedocs.io/en/stable/', None),
+ 'attrs': ('http://www.attrs.org/en/stable/', None),
 }
 
 autodoc_mock_imports = ['pandas']

hypothesis-python/src/hypothesis/strategies.py

@@ -1049,6 +1049,12 @@ def builds(
  value :const:`hypothesis.infer` as a keyword argument to
  builds, instead of a strategy for that argument to the callable.
 
+ If the callable is a class defined with :pypi:`attrs`, missing required
+ arguments may be inferred from the type, converter, or validator (for
+ :func:`~attrs:attr.validators.in_`,
+ :func:`~attrs:attr.validators.optional`, or
+ :func:`~attrs:attr.validators.instance_of` validators) of the attribute.
+
  Examples from this strategy shrink by shrinking the argument values to
  the callable.
  """