class ExceptionIsLikeMixin: def assertExceptionIsLike(self, exc, template): """ Passes when the provided `exc` matches the structure of `template`. Individual exceptions don't have to be the same objects or even pass an equality test: they only need to be the same type and contain equal `exc_obj.args`. """ if exc is None and template is None: return if template is None: self.fail(f"unexpected exception: {exc}") if exc is None: self.fail(f"expected an exception like {template!r}, got None") if not isinstance(exc, ExceptionGroup): self.assertEqual(exc.__class__, template.__class__) self.assertEqual(exc.args[0], template.args[0]) else: self.assertEqual(exc.message, template.message) self.assertEqual(len(exc.exceptions), len(template.exceptions)) for e, t in zip(exc.exceptions, template.exceptions): self.assertExceptionIsLike(e, t)