test_ok2/changelog/3632.feature.rst

Richer equality comparison introspection on ``AssertionError`` for objects created using `attrs <http://www.attrs.org/en/stable/>`_ or `dataclasses <https://docs.python.org/3/library/dataclasses.html>`_ (Python 3.7+, `backported to 3.6 <https://pypi.org/project/dataclasses>`_).