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authorS. Solomon Darnell2025-03-28 21:52:21 -0500
committerS. Solomon Darnell2025-03-28 21:52:21 -0500
commit4a52a71956a8d46fcb7294ac71734504bb09bcc2 (patch)
treeee3dc5af3b6313e921cd920906356f5d4febc4ed /.venv/lib/python3.12/site-packages/jsonschema/tests/test_validators.py
parentcc961e04ba734dd72309fb548a2f97d67d578813 (diff)
downloadgn-ai-master.tar.gz
two version of R2R are here HEAD master
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+from __future__ import annotations
+
+from collections import deque, namedtuple
+from contextlib import contextmanager
+from decimal import Decimal
+from io import BytesIO
+from typing import Any
+from unittest import TestCase, mock
+from urllib.request import pathname2url
+import json
+import os
+import sys
+import tempfile
+import warnings
+
+from attrs import define, field
+from referencing.jsonschema import DRAFT202012
+import referencing.exceptions
+
+from jsonschema import (
+    FormatChecker,
+    TypeChecker,
+    exceptions,
+    protocols,
+    validators,
+)
+
+
+def fail(validator, errors, instance, schema):
+    for each in errors:
+        each.setdefault("message", "You told me to fail!")
+        yield exceptions.ValidationError(**each)
+
+
+class TestCreateAndExtend(TestCase):
+    def setUp(self):
+        self.addCleanup(
+            self.assertEqual,
+            validators._META_SCHEMAS,
+            dict(validators._META_SCHEMAS),
+        )
+        self.addCleanup(
+            self.assertEqual,
+            validators._VALIDATORS,
+            dict(validators._VALIDATORS),
+        )
+
+        self.meta_schema = {"$id": "some://meta/schema"}
+        self.validators = {"fail": fail}
+        self.type_checker = TypeChecker()
+        self.Validator = validators.create(
+            meta_schema=self.meta_schema,
+            validators=self.validators,
+            type_checker=self.type_checker,
+        )
+
+    def test_attrs(self):
+        self.assertEqual(
+            (
+                self.Validator.VALIDATORS,
+                self.Validator.META_SCHEMA,
+                self.Validator.TYPE_CHECKER,
+            ), (
+                self.validators,
+                self.meta_schema,
+                self.type_checker,
+            ),
+        )
+
+    def test_init(self):
+        schema = {"fail": []}
+        self.assertEqual(self.Validator(schema).schema, schema)
+
+    def test_iter_errors_successful(self):
+        schema = {"fail": []}
+        validator = self.Validator(schema)
+
+        errors = list(validator.iter_errors("hello"))
+        self.assertEqual(errors, [])
+
+    def test_iter_errors_one_error(self):
+        schema = {"fail": [{"message": "Whoops!"}]}
+        validator = self.Validator(schema)
+
+        expected_error = exceptions.ValidationError(
+            "Whoops!",
+            instance="goodbye",
+            schema=schema,
+            validator="fail",
+            validator_value=[{"message": "Whoops!"}],
+            schema_path=deque(["fail"]),
+        )
+
+        errors = list(validator.iter_errors("goodbye"))
+        self.assertEqual(len(errors), 1)
+        self.assertEqual(errors[0]._contents(), expected_error._contents())
+
+    def test_iter_errors_multiple_errors(self):
+        schema = {
+            "fail": [
+                {"message": "First"},
+                {"message": "Second!", "validator": "asdf"},
+                {"message": "Third"},
+            ],
+        }
+        validator = self.Validator(schema)
+
+        errors = list(validator.iter_errors("goodbye"))
+        self.assertEqual(len(errors), 3)
+
+    def test_if_a_version_is_provided_it_is_registered(self):
+        Validator = validators.create(
+            meta_schema={"$id": "something"},
+            version="my version",
+        )
+        self.addCleanup(validators._META_SCHEMAS.pop, "something")
+        self.addCleanup(validators._VALIDATORS.pop, "my version")
+        self.assertEqual(Validator.__name__, "MyVersionValidator")
+        self.assertEqual(Validator.__qualname__, "MyVersionValidator")
+
+    def test_repr(self):
+        Validator = validators.create(
+            meta_schema={"$id": "something"},
+            version="my version",
+        )
+        self.addCleanup(validators._META_SCHEMAS.pop, "something")
+        self.addCleanup(validators._VALIDATORS.pop, "my version")
+        self.assertEqual(
+            repr(Validator({})),
+            "MyVersionValidator(schema={}, format_checker=None)",
+        )
+
+    def test_long_repr(self):
+        Validator = validators.create(
+            meta_schema={"$id": "something"},
+            version="my version",
+        )
+        self.addCleanup(validators._META_SCHEMAS.pop, "something")
+        self.addCleanup(validators._VALIDATORS.pop, "my version")
+        self.assertEqual(
+            repr(Validator({"a": list(range(1000))})), (
+                "MyVersionValidator(schema={'a': [0, 1, 2, 3, 4, 5, ...]}, "
+                "format_checker=None)"
+            ),
+        )
+
+    def test_repr_no_version(self):
+        Validator = validators.create(meta_schema={})
+        self.assertEqual(
+            repr(Validator({})),
+            "Validator(schema={}, format_checker=None)",
+        )
+
+    def test_dashes_are_stripped_from_validator_names(self):
+        Validator = validators.create(
+            meta_schema={"$id": "something"},
+            version="foo-bar",
+        )
+        self.addCleanup(validators._META_SCHEMAS.pop, "something")
+        self.addCleanup(validators._VALIDATORS.pop, "foo-bar")
+        self.assertEqual(Validator.__qualname__, "FooBarValidator")
+
+    def test_if_a_version_is_not_provided_it_is_not_registered(self):
+        original = dict(validators._META_SCHEMAS)
+        validators.create(meta_schema={"id": "id"})
+        self.assertEqual(validators._META_SCHEMAS, original)
+
+    def test_validates_registers_meta_schema_id(self):
+        meta_schema_key = "meta schema id"
+        my_meta_schema = {"id": meta_schema_key}
+
+        validators.create(
+            meta_schema=my_meta_schema,
+            version="my version",
+            id_of=lambda s: s.get("id", ""),
+        )
+        self.addCleanup(validators._META_SCHEMAS.pop, meta_schema_key)
+        self.addCleanup(validators._VALIDATORS.pop, "my version")
+
+        self.assertIn(meta_schema_key, validators._META_SCHEMAS)
+
+    def test_validates_registers_meta_schema_draft6_id(self):
+        meta_schema_key = "meta schema $id"
+        my_meta_schema = {"$id": meta_schema_key}
+
+        validators.create(
+            meta_schema=my_meta_schema,
+            version="my version",
+        )
+        self.addCleanup(validators._META_SCHEMAS.pop, meta_schema_key)
+        self.addCleanup(validators._VALIDATORS.pop, "my version")
+
+        self.assertIn(meta_schema_key, validators._META_SCHEMAS)
+
+    def test_create_default_types(self):
+        Validator = validators.create(meta_schema={}, validators=())
+        self.assertTrue(
+            all(
+                Validator({}).is_type(instance=instance, type=type)
+                for type, instance in [
+                    ("array", []),
+                    ("boolean", True),
+                    ("integer", 12),
+                    ("null", None),
+                    ("number", 12.0),
+                    ("object", {}),
+                    ("string", "foo"),
+                ]
+            ),
+        )
+
+    def test_check_schema_with_different_metaschema(self):
+        """
+        One can create a validator class whose metaschema uses a different
+        dialect than itself.
+        """
+
+        NoEmptySchemasValidator = validators.create(
+            meta_schema={
+                "$schema": validators.Draft202012Validator.META_SCHEMA["$id"],
+                "not": {"const": {}},
+            },
+        )
+        NoEmptySchemasValidator.check_schema({"foo": "bar"})
+
+        with self.assertRaises(exceptions.SchemaError):
+            NoEmptySchemasValidator.check_schema({})
+
+        NoEmptySchemasValidator({"foo": "bar"}).validate("foo")
+
+    def test_check_schema_with_different_metaschema_defaults_to_self(self):
+        """
+        A validator whose metaschema doesn't declare $schema defaults to its
+        own validation behavior, not the latest "normal" specification.
+        """
+
+        NoEmptySchemasValidator = validators.create(
+            meta_schema={"fail": [{"message": "Meta schema whoops!"}]},
+            validators={"fail": fail},
+        )
+        with self.assertRaises(exceptions.SchemaError):
+            NoEmptySchemasValidator.check_schema({})
+
+    def test_extend(self):
+        original = dict(self.Validator.VALIDATORS)
+        new = object()
+
+        Extended = validators.extend(
+            self.Validator,
+            validators={"new": new},
+        )
+        self.assertEqual(
+            (
+                Extended.VALIDATORS,
+                Extended.META_SCHEMA,
+                Extended.TYPE_CHECKER,
+                self.Validator.VALIDATORS,
+            ), (
+                dict(original, new=new),
+                self.Validator.META_SCHEMA,
+                self.Validator.TYPE_CHECKER,
+                original,
+            ),
+        )
+
+    def test_extend_idof(self):
+        """
+        Extending a validator preserves its notion of schema IDs.
+        """
+        def id_of(schema):
+            return schema.get("__test__", self.Validator.ID_OF(schema))
+        correct_id = "the://correct/id/"
+        meta_schema = {
+            "$id": "the://wrong/id/",
+            "__test__": correct_id,
+        }
+        Original = validators.create(
+            meta_schema=meta_schema,
+            validators=self.validators,
+            type_checker=self.type_checker,
+            id_of=id_of,
+        )
+        self.assertEqual(Original.ID_OF(Original.META_SCHEMA), correct_id)
+
+        Derived = validators.extend(Original)
+        self.assertEqual(Derived.ID_OF(Derived.META_SCHEMA), correct_id)
+
+    def test_extend_applicable_validators(self):
+        """
+        Extending a validator preserves its notion of applicable validators.
+        """
+
+        schema = {
+            "$defs": {"test": {"type": "number"}},
+            "$ref": "#/$defs/test",
+            "maximum": 1,
+        }
+
+        draft4 = validators.Draft4Validator(schema)
+        self.assertTrue(draft4.is_valid(37))  # as $ref ignores siblings
+
+        Derived = validators.extend(validators.Draft4Validator)
+        self.assertTrue(Derived(schema).is_valid(37))
+
+
+class TestValidationErrorMessages(TestCase):
+    def message_for(self, instance, schema, *args, **kwargs):
+        cls = kwargs.pop("cls", validators._LATEST_VERSION)
+        cls.check_schema(schema)
+        validator = cls(schema, *args, **kwargs)
+        errors = list(validator.iter_errors(instance))
+        self.assertTrue(errors, msg=f"No errors were raised for {instance!r}")
+        self.assertEqual(
+            len(errors),
+            1,
+            msg=f"Expected exactly one error, found {errors!r}",
+        )
+        return errors[0].message
+
+    def test_single_type_failure(self):
+        message = self.message_for(instance=1, schema={"type": "string"})
+        self.assertEqual(message, "1 is not of type 'string'")
+
+    def test_single_type_list_failure(self):
+        message = self.message_for(instance=1, schema={"type": ["string"]})
+        self.assertEqual(message, "1 is not of type 'string'")
+
+    def test_multiple_type_failure(self):
+        types = "string", "object"
+        message = self.message_for(instance=1, schema={"type": list(types)})
+        self.assertEqual(message, "1 is not of type 'string', 'object'")
+
+    def test_object_with_named_type_failure(self):
+        schema = {"type": [{"name": "Foo", "minimum": 3}]}
+        message = self.message_for(
+            instance=1,
+            schema=schema,
+            cls=validators.Draft3Validator,
+        )
+        self.assertEqual(message, "1 is not of type 'Foo'")
+
+    def test_minimum(self):
+        message = self.message_for(instance=1, schema={"minimum": 2})
+        self.assertEqual(message, "1 is less than the minimum of 2")
+
+    def test_maximum(self):
+        message = self.message_for(instance=1, schema={"maximum": 0})
+        self.assertEqual(message, "1 is greater than the maximum of 0")
+
+    def test_dependencies_single_element(self):
+        depend, on = "bar", "foo"
+        schema = {"dependencies": {depend: on}}
+        message = self.message_for(
+            instance={"bar": 2},
+            schema=schema,
+            cls=validators.Draft3Validator,
+        )
+        self.assertEqual(message, "'foo' is a dependency of 'bar'")
+
+    def test_object_without_title_type_failure_draft3(self):
+        type = {"type": [{"minimum": 3}]}
+        message = self.message_for(
+            instance=1,
+            schema={"type": [type]},
+            cls=validators.Draft3Validator,
+        )
+        self.assertEqual(
+            message,
+            "1 is not of type {'type': [{'minimum': 3}]}",
+        )
+
+    def test_dependencies_list_draft3(self):
+        depend, on = "bar", "foo"
+        schema = {"dependencies": {depend: [on]}}
+        message = self.message_for(
+            instance={"bar": 2},
+            schema=schema,
+            cls=validators.Draft3Validator,
+        )
+        self.assertEqual(message, "'foo' is a dependency of 'bar'")
+
+    def test_dependencies_list_draft7(self):
+        depend, on = "bar", "foo"
+        schema = {"dependencies": {depend: [on]}}
+        message = self.message_for(
+            instance={"bar": 2},
+            schema=schema,
+            cls=validators.Draft7Validator,
+        )
+        self.assertEqual(message, "'foo' is a dependency of 'bar'")
+
+    def test_additionalItems_single_failure(self):
+        message = self.message_for(
+            instance=[2],
+            schema={"items": [], "additionalItems": False},
+            cls=validators.Draft3Validator,
+        )
+        self.assertIn("(2 was unexpected)", message)
+
+    def test_additionalItems_multiple_failures(self):
+        message = self.message_for(
+            instance=[1, 2, 3],
+            schema={"items": [], "additionalItems": False},
+            cls=validators.Draft3Validator,
+        )
+        self.assertIn("(1, 2, 3 were unexpected)", message)
+
+    def test_additionalProperties_single_failure(self):
+        additional = "foo"
+        schema = {"additionalProperties": False}
+        message = self.message_for(instance={additional: 2}, schema=schema)
+        self.assertIn("('foo' was unexpected)", message)
+
+    def test_additionalProperties_multiple_failures(self):
+        schema = {"additionalProperties": False}
+        message = self.message_for(
+            instance=dict.fromkeys(["foo", "bar"]),
+            schema=schema,
+        )
+
+        self.assertIn(repr("foo"), message)
+        self.assertIn(repr("bar"), message)
+        self.assertIn("were unexpected)", message)
+
+    def test_const(self):
+        schema = {"const": 12}
+        message = self.message_for(
+            instance={"foo": "bar"},
+            schema=schema,
+        )
+        self.assertIn("12 was expected", message)
+
+    def test_contains_draft_6(self):
+        schema = {"contains": {"const": 12}}
+        message = self.message_for(
+            instance=[2, {}, []],
+            schema=schema,
+            cls=validators.Draft6Validator,
+        )
+        self.assertEqual(
+            message,
+            "None of [2, {}, []] are valid under the given schema",
+        )
+
+    def test_invalid_format_default_message(self):
+        checker = FormatChecker(formats=())
+        checker.checks("thing")(lambda value: False)
+
+        schema = {"format": "thing"}
+        message = self.message_for(
+            instance="bla",
+            schema=schema,
+            format_checker=checker,
+        )
+
+        self.assertIn(repr("bla"), message)
+        self.assertIn(repr("thing"), message)
+        self.assertIn("is not a", message)
+
+    def test_additionalProperties_false_patternProperties(self):
+        schema = {"type": "object",
+                  "additionalProperties": False,
+                  "patternProperties": {
+                      "^abc$": {"type": "string"},
+                      "^def$": {"type": "string"},
+                  }}
+        message = self.message_for(
+            instance={"zebra": 123},
+            schema=schema,
+            cls=validators.Draft4Validator,
+        )
+        self.assertEqual(
+            message,
+            "{} does not match any of the regexes: {}, {}".format(
+                repr("zebra"), repr("^abc$"), repr("^def$"),
+            ),
+        )
+        message = self.message_for(
+            instance={"zebra": 123, "fish": 456},
+            schema=schema,
+            cls=validators.Draft4Validator,
+        )
+        self.assertEqual(
+            message,
+            "{}, {} do not match any of the regexes: {}, {}".format(
+                repr("fish"), repr("zebra"), repr("^abc$"), repr("^def$"),
+            ),
+        )
+
+    def test_False_schema(self):
+        message = self.message_for(
+            instance="something",
+            schema=False,
+        )
+        self.assertEqual(message, "False schema does not allow 'something'")
+
+    def test_multipleOf(self):
+        message = self.message_for(
+            instance=3,
+            schema={"multipleOf": 2},
+        )
+        self.assertEqual(message, "3 is not a multiple of 2")
+
+    def test_minItems(self):
+        message = self.message_for(instance=[], schema={"minItems": 2})
+        self.assertEqual(message, "[] is too short")
+
+    def test_maxItems(self):
+        message = self.message_for(instance=[1, 2, 3], schema={"maxItems": 2})
+        self.assertEqual(message, "[1, 2, 3] is too long")
+
+    def test_minItems_1(self):
+        message = self.message_for(instance=[], schema={"minItems": 1})
+        self.assertEqual(message, "[] should be non-empty")
+
+    def test_maxItems_0(self):
+        message = self.message_for(instance=[1, 2, 3], schema={"maxItems": 0})
+        self.assertEqual(message, "[1, 2, 3] is expected to be empty")
+
+    def test_minLength(self):
+        message = self.message_for(
+            instance="",
+            schema={"minLength": 2},
+        )
+        self.assertEqual(message, "'' is too short")
+
+    def test_maxLength(self):
+        message = self.message_for(
+            instance="abc",
+            schema={"maxLength": 2},
+        )
+        self.assertEqual(message, "'abc' is too long")
+
+    def test_minLength_1(self):
+        message = self.message_for(instance="", schema={"minLength": 1})
+        self.assertEqual(message, "'' should be non-empty")
+
+    def test_maxLength_0(self):
+        message = self.message_for(instance="abc", schema={"maxLength": 0})
+        self.assertEqual(message, "'abc' is expected to be empty")
+
+    def test_minProperties(self):
+        message = self.message_for(instance={}, schema={"minProperties": 2})
+        self.assertEqual(message, "{} does not have enough properties")
+
+    def test_maxProperties(self):
+        message = self.message_for(
+            instance={"a": {}, "b": {}, "c": {}},
+            schema={"maxProperties": 2},
+        )
+        self.assertEqual(
+            message,
+            "{'a': {}, 'b': {}, 'c': {}} has too many properties",
+        )
+
+    def test_minProperties_1(self):
+        message = self.message_for(instance={}, schema={"minProperties": 1})
+        self.assertEqual(message, "{} should be non-empty")
+
+    def test_maxProperties_0(self):
+        message = self.message_for(
+            instance={1: 2},
+            schema={"maxProperties": 0},
+        )
+        self.assertEqual(message, "{1: 2} is expected to be empty")
+
+    def test_prefixItems_with_items(self):
+        message = self.message_for(
+            instance=[1, 2, "foo"],
+            schema={"items": False, "prefixItems": [{}, {}]},
+        )
+        self.assertEqual(
+            message,
+            "Expected at most 2 items but found 1 extra: 'foo'",
+        )
+
+    def test_prefixItems_with_multiple_extra_items(self):
+        message = self.message_for(
+            instance=[1, 2, "foo", 5],
+            schema={"items": False, "prefixItems": [{}, {}]},
+        )
+        self.assertEqual(
+            message,
+            "Expected at most 2 items but found 2 extra: ['foo', 5]",
+        )
+
+    def test_pattern(self):
+        message = self.message_for(
+            instance="bbb",
+            schema={"pattern": "^a*$"},
+        )
+        self.assertEqual(message, "'bbb' does not match '^a*$'")
+
+    def test_does_not_contain(self):
+        message = self.message_for(
+            instance=[],
+            schema={"contains": {"type": "string"}},
+        )
+        self.assertEqual(
+            message,
+            "[] does not contain items matching the given schema",
+        )
+
+    def test_contains_too_few(self):
+        message = self.message_for(
+            instance=["foo", 1],
+            schema={"contains": {"type": "string"}, "minContains": 2},
+        )
+        self.assertEqual(
+            message,
+            "Too few items match the given schema "
+            "(expected at least 2 but only 1 matched)",
+        )
+
+    def test_contains_too_few_both_constrained(self):
+        message = self.message_for(
+            instance=["foo", 1],
+            schema={
+                "contains": {"type": "string"},
+                "minContains": 2,
+                "maxContains": 4,
+            },
+        )
+        self.assertEqual(
+            message,
+            "Too few items match the given schema (expected at least 2 but "
+            "only 1 matched)",
+        )
+
+    def test_contains_too_many(self):
+        message = self.message_for(
+            instance=["foo", "bar", "baz"],
+            schema={"contains": {"type": "string"}, "maxContains": 2},
+        )
+        self.assertEqual(
+            message,
+            "Too many items match the given schema (expected at most 2)",
+        )
+
+    def test_contains_too_many_both_constrained(self):
+        message = self.message_for(
+            instance=["foo"] * 5,
+            schema={
+                "contains": {"type": "string"},
+                "minContains": 2,
+                "maxContains": 4,
+            },
+        )
+        self.assertEqual(
+            message,
+            "Too many items match the given schema (expected at most 4)",
+        )
+
+    def test_exclusiveMinimum(self):
+        message = self.message_for(
+            instance=3,
+            schema={"exclusiveMinimum": 5},
+        )
+        self.assertEqual(
+            message,
+            "3 is less than or equal to the minimum of 5",
+        )
+
+    def test_exclusiveMaximum(self):
+        message = self.message_for(instance=3, schema={"exclusiveMaximum": 2})
+        self.assertEqual(
+            message,
+            "3 is greater than or equal to the maximum of 2",
+        )
+
+    def test_required(self):
+        message = self.message_for(instance={}, schema={"required": ["foo"]})
+        self.assertEqual(message, "'foo' is a required property")
+
+    def test_dependentRequired(self):
+        message = self.message_for(
+            instance={"foo": {}},
+            schema={"dependentRequired": {"foo": ["bar"]}},
+        )
+        self.assertEqual(message, "'bar' is a dependency of 'foo'")
+
+    def test_oneOf_matches_none(self):
+        message = self.message_for(instance={}, schema={"oneOf": [False]})
+        self.assertEqual(
+            message,
+            "{} is not valid under any of the given schemas",
+        )
+
+    def test_oneOf_matches_too_many(self):
+        message = self.message_for(instance={}, schema={"oneOf": [True, True]})
+        self.assertEqual(message, "{} is valid under each of True, True")
+
+    def test_unevaluated_items(self):
+        schema = {"type": "array", "unevaluatedItems": False}
+        message = self.message_for(instance=["foo", "bar"], schema=schema)
+        self.assertIn(
+            message,
+            "Unevaluated items are not allowed ('foo', 'bar' were unexpected)",
+        )
+
+    def test_unevaluated_items_on_invalid_type(self):
+        schema = {"type": "array", "unevaluatedItems": False}
+        message = self.message_for(instance="foo", schema=schema)
+        self.assertEqual(message, "'foo' is not of type 'array'")
+
+    def test_unevaluated_properties_invalid_against_subschema(self):
+        schema = {
+            "properties": {"foo": {"type": "string"}},
+            "unevaluatedProperties": {"const": 12},
+        }
+        message = self.message_for(
+            instance={
+                "foo": "foo",
+                "bar": "bar",
+                "baz": 12,
+            },
+            schema=schema,
+        )
+        self.assertEqual(
+            message,
+            "Unevaluated properties are not valid under the given schema "
+            "('bar' was unevaluated and invalid)",
+        )
+
+    def test_unevaluated_properties_disallowed(self):
+        schema = {"type": "object", "unevaluatedProperties": False}
+        message = self.message_for(
+            instance={
+                "foo": "foo",
+                "bar": "bar",
+            },
+            schema=schema,
+        )
+        self.assertEqual(
+            message,
+            "Unevaluated properties are not allowed "
+            "('bar', 'foo' were unexpected)",
+        )
+
+    def test_unevaluated_properties_on_invalid_type(self):
+        schema = {"type": "object", "unevaluatedProperties": False}
+        message = self.message_for(instance="foo", schema=schema)
+        self.assertEqual(message, "'foo' is not of type 'object'")
+
+    def test_single_item(self):
+        schema = {"prefixItems": [{}], "items": False}
+        message = self.message_for(
+            instance=["foo", "bar", "baz"],
+            schema=schema,
+        )
+        self.assertEqual(
+            message,
+            "Expected at most 1 item but found 2 extra: ['bar', 'baz']",
+        )
+
+    def test_heterogeneous_additionalItems_with_Items(self):
+        schema = {"items": [{}], "additionalItems": False}
+        message = self.message_for(
+            instance=["foo", "bar", 37],
+            schema=schema,
+            cls=validators.Draft7Validator,
+        )
+        self.assertEqual(
+            message,
+            "Additional items are not allowed ('bar', 37 were unexpected)",
+        )
+
+    def test_heterogeneous_items_prefixItems(self):
+        schema = {"prefixItems": [{}], "items": False}
+        message = self.message_for(
+            instance=["foo", "bar", 37],
+            schema=schema,
+        )
+        self.assertEqual(
+            message,
+            "Expected at most 1 item but found 2 extra: ['bar', 37]",
+        )
+
+    def test_heterogeneous_unevaluatedItems_prefixItems(self):
+        schema = {"prefixItems": [{}], "unevaluatedItems": False}
+        message = self.message_for(
+            instance=["foo", "bar", 37],
+            schema=schema,
+        )
+        self.assertEqual(
+            message,
+            "Unevaluated items are not allowed ('bar', 37 were unexpected)",
+        )
+
+    def test_heterogeneous_properties_additionalProperties(self):
+        """
+        Not valid deserialized JSON, but this should not blow up.
+        """
+        schema = {"properties": {"foo": {}}, "additionalProperties": False}
+        message = self.message_for(
+            instance={"foo": {}, "a": "baz", 37: 12},
+            schema=schema,
+        )
+        self.assertEqual(
+            message,
+            "Additional properties are not allowed (37, 'a' were unexpected)",
+        )
+
+    def test_heterogeneous_properties_unevaluatedProperties(self):
+        """
+        Not valid deserialized JSON, but this should not blow up.
+        """
+        schema = {"properties": {"foo": {}}, "unevaluatedProperties": False}
+        message = self.message_for(
+            instance={"foo": {}, "a": "baz", 37: 12},
+            schema=schema,
+        )
+        self.assertEqual(
+            message,
+            "Unevaluated properties are not allowed (37, 'a' were unexpected)",
+        )
+
+
+class TestValidationErrorDetails(TestCase):
+    # TODO: These really need unit tests for each individual keyword, rather
+    #       than just these higher level tests.
+    def test_anyOf(self):
+        instance = 5
+        schema = {
+            "anyOf": [
+                {"minimum": 20},
+                {"type": "string"},
+            ],
+        }
+
+        validator = validators.Draft4Validator(schema)
+        errors = list(validator.iter_errors(instance))
+        self.assertEqual(len(errors), 1)
+        e = errors[0]
+
+        self.assertEqual(e.validator, "anyOf")
+        self.assertEqual(e.validator_value, schema["anyOf"])
+        self.assertEqual(e.instance, instance)
+        self.assertEqual(e.schema, schema)
+        self.assertIsNone(e.parent)
+
+        self.assertEqual(e.path, deque([]))
+        self.assertEqual(e.relative_path, deque([]))
+        self.assertEqual(e.absolute_path, deque([]))
+        self.assertEqual(e.json_path, "$")
+
+        self.assertEqual(e.schema_path, deque(["anyOf"]))
+        self.assertEqual(e.relative_schema_path, deque(["anyOf"]))
+        self.assertEqual(e.absolute_schema_path, deque(["anyOf"]))
+
+        self.assertEqual(len(e.context), 2)
+
+        e1, e2 = sorted_errors(e.context)
+
+        self.assertEqual(e1.validator, "minimum")
+        self.assertEqual(e1.validator_value, schema["anyOf"][0]["minimum"])
+        self.assertEqual(e1.instance, instance)
+        self.assertEqual(e1.schema, schema["anyOf"][0])
+        self.assertIs(e1.parent, e)
+
+        self.assertEqual(e1.path, deque([]))
+        self.assertEqual(e1.absolute_path, deque([]))
+        self.assertEqual(e1.relative_path, deque([]))
+        self.assertEqual(e1.json_path, "$")
+
+        self.assertEqual(e1.schema_path, deque([0, "minimum"]))
+        self.assertEqual(e1.relative_schema_path, deque([0, "minimum"]))
+        self.assertEqual(
+            e1.absolute_schema_path, deque(["anyOf", 0, "minimum"]),
+        )
+
+        self.assertFalse(e1.context)
+
+        self.assertEqual(e2.validator, "type")
+        self.assertEqual(e2.validator_value, schema["anyOf"][1]["type"])
+        self.assertEqual(e2.instance, instance)
+        self.assertEqual(e2.schema, schema["anyOf"][1])
+        self.assertIs(e2.parent, e)
+
+        self.assertEqual(e2.path, deque([]))
+        self.assertEqual(e2.relative_path, deque([]))
+        self.assertEqual(e2.absolute_path, deque([]))
+        self.assertEqual(e2.json_path, "$")
+
+        self.assertEqual(e2.schema_path, deque([1, "type"]))
+        self.assertEqual(e2.relative_schema_path, deque([1, "type"]))
+        self.assertEqual(e2.absolute_schema_path, deque(["anyOf", 1, "type"]))
+
+        self.assertEqual(len(e2.context), 0)
+
+    def test_type(self):
+        instance = {"foo": 1}
+        schema = {
+            "type": [
+                {"type": "integer"},
+                {
+                    "type": "object",
+                    "properties": {"foo": {"enum": [2]}},
+                },
+            ],
+        }
+
+        validator = validators.Draft3Validator(schema)
+        errors = list(validator.iter_errors(instance))
+        self.assertEqual(len(errors), 1)
+        e = errors[0]
+
+        self.assertEqual(e.validator, "type")
+        self.assertEqual(e.validator_value, schema["type"])
+        self.assertEqual(e.instance, instance)
+        self.assertEqual(e.schema, schema)
+        self.assertIsNone(e.parent)
+
+        self.assertEqual(e.path, deque([]))
+        self.assertEqual(e.relative_path, deque([]))
+        self.assertEqual(e.absolute_path, deque([]))
+        self.assertEqual(e.json_path, "$")
+
+        self.assertEqual(e.schema_path, deque(["type"]))
+        self.assertEqual(e.relative_schema_path, deque(["type"]))
+        self.assertEqual(e.absolute_schema_path, deque(["type"]))
+
+        self.assertEqual(len(e.context), 2)
+
+        e1, e2 = sorted_errors(e.context)
+
+        self.assertEqual(e1.validator, "type")
+        self.assertEqual(e1.validator_value, schema["type"][0]["type"])
+        self.assertEqual(e1.instance, instance)
+        self.assertEqual(e1.schema, schema["type"][0])
+        self.assertIs(e1.parent, e)
+
+        self.assertEqual(e1.path, deque([]))
+        self.assertEqual(e1.relative_path, deque([]))
+        self.assertEqual(e1.absolute_path, deque([]))
+        self.assertEqual(e1.json_path, "$")
+
+        self.assertEqual(e1.schema_path, deque([0, "type"]))
+        self.assertEqual(e1.relative_schema_path, deque([0, "type"]))
+        self.assertEqual(e1.absolute_schema_path, deque(["type", 0, "type"]))
+
+        self.assertFalse(e1.context)
+
+        self.assertEqual(e2.validator, "enum")
+        self.assertEqual(e2.validator_value, [2])
+        self.assertEqual(e2.instance, 1)
+        self.assertEqual(e2.schema, {"enum": [2]})
+        self.assertIs(e2.parent, e)
+
+        self.assertEqual(e2.path, deque(["foo"]))
+        self.assertEqual(e2.relative_path, deque(["foo"]))
+        self.assertEqual(e2.absolute_path, deque(["foo"]))
+        self.assertEqual(e2.json_path, "$.foo")
+
+        self.assertEqual(
+            e2.schema_path, deque([1, "properties", "foo", "enum"]),
+        )
+        self.assertEqual(
+            e2.relative_schema_path, deque([1, "properties", "foo", "enum"]),
+        )
+        self.assertEqual(
+            e2.absolute_schema_path,
+            deque(["type", 1, "properties", "foo", "enum"]),
+        )
+
+        self.assertFalse(e2.context)
+
+    def test_single_nesting(self):
+        instance = {"foo": 2, "bar": [1], "baz": 15, "quux": "spam"}
+        schema = {
+            "properties": {
+                "foo": {"type": "string"},
+                "bar": {"minItems": 2},
+                "baz": {"maximum": 10, "enum": [2, 4, 6, 8]},
+            },
+        }
+
+        validator = validators.Draft3Validator(schema)
+        errors = validator.iter_errors(instance)
+        e1, e2, e3, e4 = sorted_errors(errors)
+
+        self.assertEqual(e1.path, deque(["bar"]))
+        self.assertEqual(e2.path, deque(["baz"]))
+        self.assertEqual(e3.path, deque(["baz"]))
+        self.assertEqual(e4.path, deque(["foo"]))
+
+        self.assertEqual(e1.relative_path, deque(["bar"]))
+        self.assertEqual(e2.relative_path, deque(["baz"]))
+        self.assertEqual(e3.relative_path, deque(["baz"]))
+        self.assertEqual(e4.relative_path, deque(["foo"]))
+
+        self.assertEqual(e1.absolute_path, deque(["bar"]))
+        self.assertEqual(e2.absolute_path, deque(["baz"]))
+        self.assertEqual(e3.absolute_path, deque(["baz"]))
+        self.assertEqual(e4.absolute_path, deque(["foo"]))
+
+        self.assertEqual(e1.json_path, "$.bar")
+        self.assertEqual(e2.json_path, "$.baz")
+        self.assertEqual(e3.json_path, "$.baz")
+        self.assertEqual(e4.json_path, "$.foo")
+
+        self.assertEqual(e1.validator, "minItems")
+        self.assertEqual(e2.validator, "enum")
+        self.assertEqual(e3.validator, "maximum")
+        self.assertEqual(e4.validator, "type")
+
+    def test_multiple_nesting(self):
+        instance = [1, {"foo": 2, "bar": {"baz": [1]}}, "quux"]
+        schema = {
+            "type": "string",
+            "items": {
+                "type": ["string", "object"],
+                "properties": {
+                    "foo": {"enum": [1, 3]},
+                    "bar": {
+                        "type": "array",
+                        "properties": {
+                            "bar": {"required": True},
+                            "baz": {"minItems": 2},
+                        },
+                    },
+                },
+            },
+        }
+
+        validator = validators.Draft3Validator(schema)
+        errors = validator.iter_errors(instance)
+        e1, e2, e3, e4, e5, e6 = sorted_errors(errors)
+
+        self.assertEqual(e1.path, deque([]))
+        self.assertEqual(e2.path, deque([0]))
+        self.assertEqual(e3.path, deque([1, "bar"]))
+        self.assertEqual(e4.path, deque([1, "bar", "bar"]))
+        self.assertEqual(e5.path, deque([1, "bar", "baz"]))
+        self.assertEqual(e6.path, deque([1, "foo"]))
+
+        self.assertEqual(e1.json_path, "$")
+        self.assertEqual(e2.json_path, "$[0]")
+        self.assertEqual(e3.json_path, "$[1].bar")
+        self.assertEqual(e4.json_path, "$[1].bar.bar")
+        self.assertEqual(e5.json_path, "$[1].bar.baz")
+        self.assertEqual(e6.json_path, "$[1].foo")
+
+        self.assertEqual(e1.schema_path, deque(["type"]))
+        self.assertEqual(e2.schema_path, deque(["items", "type"]))
+        self.assertEqual(
+            list(e3.schema_path), ["items", "properties", "bar", "type"],
+        )
+        self.assertEqual(
+            list(e4.schema_path),
+            ["items", "properties", "bar", "properties", "bar", "required"],
+        )
+        self.assertEqual(
+            list(e5.schema_path),
+            ["items", "properties", "bar", "properties", "baz", "minItems"],
+        )
+        self.assertEqual(
+            list(e6.schema_path), ["items", "properties", "foo", "enum"],
+        )
+
+        self.assertEqual(e1.validator, "type")
+        self.assertEqual(e2.validator, "type")
+        self.assertEqual(e3.validator, "type")
+        self.assertEqual(e4.validator, "required")
+        self.assertEqual(e5.validator, "minItems")
+        self.assertEqual(e6.validator, "enum")
+
+    def test_recursive(self):
+        schema = {
+            "definitions": {
+                "node": {
+                    "anyOf": [{
+                        "type": "object",
+                        "required": ["name", "children"],
+                        "properties": {
+                            "name": {
+                                "type": "string",
+                            },
+                            "children": {
+                                "type": "object",
+                                "patternProperties": {
+                                    "^.*$": {
+                                        "$ref": "#/definitions/node",
+                                    },
+                                },
+                            },
+                        },
+                    }],
+                },
+            },
+            "type": "object",
+            "required": ["root"],
+            "properties": {"root": {"$ref": "#/definitions/node"}},
+        }
+
+        instance = {
+            "root": {
+                "name": "root",
+                "children": {
+                    "a": {
+                        "name": "a",
+                        "children": {
+                            "ab": {
+                                "name": "ab",
+                                # missing "children"
+                            },
+                        },
+                    },
+                },
+            },
+        }
+        validator = validators.Draft4Validator(schema)
+
+        e, = validator.iter_errors(instance)
+        self.assertEqual(e.absolute_path, deque(["root"]))
+        self.assertEqual(
+            e.absolute_schema_path, deque(["properties", "root", "anyOf"]),
+        )
+        self.assertEqual(e.json_path, "$.root")
+
+        e1, = e.context
+        self.assertEqual(e1.absolute_path, deque(["root", "children", "a"]))
+        self.assertEqual(
+            e1.absolute_schema_path, deque(
+                [
+                    "properties",
+                    "root",
+                    "anyOf",
+                    0,
+                    "properties",
+                    "children",
+                    "patternProperties",
+                    "^.*$",
+                    "anyOf",
+                ],
+            ),
+        )
+        self.assertEqual(e1.json_path, "$.root.children.a")
+
+        e2, = e1.context
+        self.assertEqual(
+            e2.absolute_path, deque(
+                ["root", "children", "a", "children", "ab"],
+            ),
+        )
+        self.assertEqual(
+            e2.absolute_schema_path, deque(
+                [
+                    "properties",
+                    "root",
+                    "anyOf",
+                    0,
+                    "properties",
+                    "children",
+                    "patternProperties",
+                    "^.*$",
+                    "anyOf",
+                    0,
+                    "properties",
+                    "children",
+                    "patternProperties",
+                    "^.*$",
+                    "anyOf",
+                ],
+            ),
+        )
+        self.assertEqual(e2.json_path, "$.root.children.a.children.ab")
+
+    def test_additionalProperties(self):
+        instance = {"bar": "bar", "foo": 2}
+        schema = {"additionalProperties": {"type": "integer", "minimum": 5}}
+
+        validator = validators.Draft3Validator(schema)
+        errors = validator.iter_errors(instance)
+        e1, e2 = sorted_errors(errors)
+
+        self.assertEqual(e1.path, deque(["bar"]))
+        self.assertEqual(e2.path, deque(["foo"]))
+
+        self.assertEqual(e1.json_path, "$.bar")
+        self.assertEqual(e2.json_path, "$.foo")
+
+        self.assertEqual(e1.validator, "type")
+        self.assertEqual(e2.validator, "minimum")
+
+    def test_patternProperties(self):
+        instance = {"bar": 1, "foo": 2}
+        schema = {
+            "patternProperties": {
+                "bar": {"type": "string"},
+                "foo": {"minimum": 5},
+            },
+        }
+
+        validator = validators.Draft3Validator(schema)
+        errors = validator.iter_errors(instance)
+        e1, e2 = sorted_errors(errors)
+
+        self.assertEqual(e1.path, deque(["bar"]))
+        self.assertEqual(e2.path, deque(["foo"]))
+
+        self.assertEqual(e1.json_path, "$.bar")
+        self.assertEqual(e2.json_path, "$.foo")
+
+        self.assertEqual(e1.validator, "type")
+        self.assertEqual(e2.validator, "minimum")
+
+    def test_additionalItems(self):
+        instance = ["foo", 1]
+        schema = {
+            "items": [],
+            "additionalItems": {"type": "integer", "minimum": 5},
+        }
+
+        validator = validators.Draft3Validator(schema)
+        errors = validator.iter_errors(instance)
+        e1, e2 = sorted_errors(errors)
+
+        self.assertEqual(e1.path, deque([0]))
+        self.assertEqual(e2.path, deque([1]))
+
+        self.assertEqual(e1.json_path, "$[0]")
+        self.assertEqual(e2.json_path, "$[1]")
+
+        self.assertEqual(e1.validator, "type")
+        self.assertEqual(e2.validator, "minimum")
+
+    def test_additionalItems_with_items(self):
+        instance = ["foo", "bar", 1]
+        schema = {
+            "items": [{}],
+            "additionalItems": {"type": "integer", "minimum": 5},
+        }
+
+        validator = validators.Draft3Validator(schema)
+        errors = validator.iter_errors(instance)
+        e1, e2 = sorted_errors(errors)
+
+        self.assertEqual(e1.path, deque([1]))
+        self.assertEqual(e2.path, deque([2]))
+
+        self.assertEqual(e1.json_path, "$[1]")
+        self.assertEqual(e2.json_path, "$[2]")
+
+        self.assertEqual(e1.validator, "type")
+        self.assertEqual(e2.validator, "minimum")
+
+    def test_propertyNames(self):
+        instance = {"foo": 12}
+        schema = {"propertyNames": {"not": {"const": "foo"}}}
+
+        validator = validators.Draft7Validator(schema)
+        error, = validator.iter_errors(instance)
+
+        self.assertEqual(error.validator, "not")
+        self.assertEqual(
+            error.message,
+            "'foo' should not be valid under {'const': 'foo'}",
+        )
+        self.assertEqual(error.path, deque([]))
+        self.assertEqual(error.json_path, "$")
+        self.assertEqual(error.schema_path, deque(["propertyNames", "not"]))
+
+    def test_if_then(self):
+        schema = {
+            "if": {"const": 12},
+            "then": {"const": 13},
+        }
+
+        validator = validators.Draft7Validator(schema)
+        error, = validator.iter_errors(12)
+
+        self.assertEqual(error.validator, "const")
+        self.assertEqual(error.message, "13 was expected")
+        self.assertEqual(error.path, deque([]))
+        self.assertEqual(error.json_path, "$")
+        self.assertEqual(error.schema_path, deque(["then", "const"]))
+
+    def test_if_else(self):
+        schema = {
+            "if": {"const": 12},
+            "else": {"const": 13},
+        }
+
+        validator = validators.Draft7Validator(schema)
+        error, = validator.iter_errors(15)
+
+        self.assertEqual(error.validator, "const")
+        self.assertEqual(error.message, "13 was expected")
+        self.assertEqual(error.path, deque([]))
+        self.assertEqual(error.json_path, "$")
+        self.assertEqual(error.schema_path, deque(["else", "const"]))
+
+    def test_boolean_schema_False(self):
+        validator = validators.Draft7Validator(False)
+        error, = validator.iter_errors(12)
+
+        self.assertEqual(
+            (
+                error.message,
+                error.validator,
+                error.validator_value,
+                error.instance,
+                error.schema,
+                error.schema_path,
+                error.json_path,
+            ),
+            (
+                "False schema does not allow 12",
+                None,
+                None,
+                12,
+                False,
+                deque([]),
+                "$",
+            ),
+        )
+
+    def test_ref(self):
+        ref, schema = "someRef", {"additionalProperties": {"type": "integer"}}
+        validator = validators.Draft7Validator(
+            {"$ref": ref},
+            resolver=validators._RefResolver("", {}, store={ref: schema}),
+        )
+        error, = validator.iter_errors({"foo": "notAnInteger"})
+
+        self.assertEqual(
+            (
+                error.message,
+                error.validator,
+                error.validator_value,
+                error.instance,
+                error.absolute_path,
+                error.schema,
+                error.schema_path,
+                error.json_path,
+            ),
+            (
+                "'notAnInteger' is not of type 'integer'",
+                "type",
+                "integer",
+                "notAnInteger",
+                deque(["foo"]),
+                {"type": "integer"},
+                deque(["additionalProperties", "type"]),
+                "$.foo",
+            ),
+        )
+
+    def test_prefixItems(self):
+        schema = {"prefixItems": [{"type": "string"}, {}, {}, {"maximum": 3}]}
+        validator = validators.Draft202012Validator(schema)
+        type_error, min_error = validator.iter_errors([1, 2, "foo", 5])
+        self.assertEqual(
+            (
+                type_error.message,
+                type_error.validator,
+                type_error.validator_value,
+                type_error.instance,
+                type_error.absolute_path,
+                type_error.schema,
+                type_error.schema_path,
+                type_error.json_path,
+            ),
+            (
+                "1 is not of type 'string'",
+                "type",
+                "string",
+                1,
+                deque([0]),
+                {"type": "string"},
+                deque(["prefixItems", 0, "type"]),
+                "$[0]",
+            ),
+        )
+        self.assertEqual(
+            (
+                min_error.message,
+                min_error.validator,
+                min_error.validator_value,
+                min_error.instance,
+                min_error.absolute_path,
+                min_error.schema,
+                min_error.schema_path,
+                min_error.json_path,
+            ),
+            (
+                "5 is greater than the maximum of 3",
+                "maximum",
+                3,
+                5,
+                deque([3]),
+                {"maximum": 3},
+                deque(["prefixItems", 3, "maximum"]),
+                "$[3]",
+            ),
+        )
+
+    def test_prefixItems_with_items(self):
+        schema = {
+            "items": {"type": "string"},
+            "prefixItems": [{}],
+        }
+        validator = validators.Draft202012Validator(schema)
+        e1, e2 = validator.iter_errors(["foo", 2, "bar", 4, "baz"])
+        self.assertEqual(
+            (
+                e1.message,
+                e1.validator,
+                e1.validator_value,
+                e1.instance,
+                e1.absolute_path,
+                e1.schema,
+                e1.schema_path,
+                e1.json_path,
+            ),
+            (
+                "2 is not of type 'string'",
+                "type",
+                "string",
+                2,
+                deque([1]),
+                {"type": "string"},
+                deque(["items", "type"]),
+                "$[1]",
+            ),
+        )
+        self.assertEqual(
+            (
+                e2.message,
+                e2.validator,
+                e2.validator_value,
+                e2.instance,
+                e2.absolute_path,
+                e2.schema,
+                e2.schema_path,
+                e2.json_path,
+            ),
+            (
+                "4 is not of type 'string'",
+                "type",
+                "string",
+                4,
+                deque([3]),
+                {"type": "string"},
+                deque(["items", "type"]),
+                "$[3]",
+            ),
+        )
+
+    def test_contains_too_many(self):
+        """
+        `contains` + `maxContains` produces only one error, even if there are
+        many more incorrectly matching elements.
+        """
+        schema = {"contains": {"type": "string"}, "maxContains": 2}
+        validator = validators.Draft202012Validator(schema)
+        error, = validator.iter_errors(["foo", 2, "bar", 4, "baz", "quux"])
+        self.assertEqual(
+            (
+                error.message,
+                error.validator,
+                error.validator_value,
+                error.instance,
+                error.absolute_path,
+                error.schema,
+                error.schema_path,
+                error.json_path,
+            ),
+            (
+                "Too many items match the given schema (expected at most 2)",
+                "maxContains",
+                2,
+                ["foo", 2, "bar", 4, "baz", "quux"],
+                deque([]),
+                {"contains": {"type": "string"}, "maxContains": 2},
+                deque(["contains"]),
+                "$",
+            ),
+        )
+
+    def test_contains_too_few(self):
+        schema = {"contains": {"type": "string"}, "minContains": 2}
+        validator = validators.Draft202012Validator(schema)
+        error, = validator.iter_errors(["foo", 2, 4])
+        self.assertEqual(
+            (
+                error.message,
+                error.validator,
+                error.validator_value,
+                error.instance,
+                error.absolute_path,
+                error.schema,
+                error.schema_path,
+                error.json_path,
+            ),
+            (
+                (
+                    "Too few items match the given schema "
+                    "(expected at least 2 but only 1 matched)"
+                ),
+                "minContains",
+                2,
+                ["foo", 2, 4],
+                deque([]),
+                {"contains": {"type": "string"}, "minContains": 2},
+                deque(["contains"]),
+                "$",
+            ),
+        )
+
+    def test_contains_none(self):
+        schema = {"contains": {"type": "string"}, "minContains": 2}
+        validator = validators.Draft202012Validator(schema)
+        error, = validator.iter_errors([2, 4])
+        self.assertEqual(
+            (
+                error.message,
+                error.validator,
+                error.validator_value,
+                error.instance,
+                error.absolute_path,
+                error.schema,
+                error.schema_path,
+                error.json_path,
+            ),
+            (
+                "[2, 4] does not contain items matching the given schema",
+                "contains",
+                {"type": "string"},
+                [2, 4],
+                deque([]),
+                {"contains": {"type": "string"}, "minContains": 2},
+                deque(["contains"]),
+                "$",
+            ),
+        )
+
+    def test_ref_sibling(self):
+        schema = {
+            "$defs": {"foo": {"required": ["bar"]}},
+            "properties": {
+                "aprop": {
+                    "$ref": "#/$defs/foo",
+                    "required": ["baz"],
+                },
+            },
+        }
+
+        validator = validators.Draft202012Validator(schema)
+        e1, e2 = validator.iter_errors({"aprop": {}})
+        self.assertEqual(
+            (
+                e1.message,
+                e1.validator,
+                e1.validator_value,
+                e1.instance,
+                e1.absolute_path,
+                e1.schema,
+                e1.schema_path,
+                e1.relative_schema_path,
+                e1.json_path,
+            ),
+            (
+                "'bar' is a required property",
+                "required",
+                ["bar"],
+                {},
+                deque(["aprop"]),
+                {"required": ["bar"]},
+                deque(["properties", "aprop", "required"]),
+                deque(["properties", "aprop", "required"]),
+                "$.aprop",
+            ),
+        )
+        self.assertEqual(
+            (
+                e2.message,
+                e2.validator,
+                e2.validator_value,
+                e2.instance,
+                e2.absolute_path,
+                e2.schema,
+                e2.schema_path,
+                e2.relative_schema_path,
+                e2.json_path,
+            ),
+            (
+                "'baz' is a required property",
+                "required",
+                ["baz"],
+                {},
+                deque(["aprop"]),
+                {"$ref": "#/$defs/foo", "required": ["baz"]},
+                deque(["properties", "aprop", "required"]),
+                deque(["properties", "aprop", "required"]),
+                "$.aprop",
+            ),
+        )
+
+
+class MetaSchemaTestsMixin:
+    # TODO: These all belong upstream
+    def test_invalid_properties(self):
+        with self.assertRaises(exceptions.SchemaError):
+            self.Validator.check_schema({"properties": 12})
+
+    def test_minItems_invalid_string(self):
+        with self.assertRaises(exceptions.SchemaError):
+            # needs to be an integer
+            self.Validator.check_schema({"minItems": "1"})
+
+    def test_enum_allows_empty_arrays(self):
+        """
+        Technically, all the spec says is they SHOULD have elements, not MUST.
+
+        (As of Draft 6. Previous drafts do say MUST).
+
+        See #529.
+        """
+        if self.Validator in {
+            validators.Draft3Validator,
+            validators.Draft4Validator,
+        }:
+            with self.assertRaises(exceptions.SchemaError):
+                self.Validator.check_schema({"enum": []})
+        else:
+            self.Validator.check_schema({"enum": []})
+
+    def test_enum_allows_non_unique_items(self):
+        """
+        Technically, all the spec says is they SHOULD be unique, not MUST.
+
+        (As of Draft 6. Previous drafts do say MUST).
+
+        See #529.
+        """
+        if self.Validator in {
+            validators.Draft3Validator,
+            validators.Draft4Validator,
+        }:
+            with self.assertRaises(exceptions.SchemaError):
+                self.Validator.check_schema({"enum": [12, 12]})
+        else:
+            self.Validator.check_schema({"enum": [12, 12]})
+
+    def test_schema_with_invalid_regex(self):
+        with self.assertRaises(exceptions.SchemaError):
+            self.Validator.check_schema({"pattern": "*notaregex"})
+
+    def test_schema_with_invalid_regex_with_disabled_format_validation(self):
+        self.Validator.check_schema(
+            {"pattern": "*notaregex"},
+            format_checker=None,
+        )
+
+
+class ValidatorTestMixin(MetaSchemaTestsMixin):
+    def test_it_implements_the_validator_protocol(self):
+        self.assertIsInstance(self.Validator({}), protocols.Validator)
+
+    def test_valid_instances_are_valid(self):
+        schema, instance = self.valid
+        self.assertTrue(self.Validator(schema).is_valid(instance))
+
+    def test_invalid_instances_are_not_valid(self):
+        schema, instance = self.invalid
+        self.assertFalse(self.Validator(schema).is_valid(instance))
+
+    def test_non_existent_properties_are_ignored(self):
+        self.Validator({object(): object()}).validate(instance=object())
+
+    def test_evolve(self):
+        schema, format_checker = {"type": "integer"}, FormatChecker()
+        original = self.Validator(
+            schema,
+            format_checker=format_checker,
+        )
+        new = original.evolve(
+            schema={"type": "string"},
+            format_checker=self.Validator.FORMAT_CHECKER,
+        )
+
+        expected = self.Validator(
+            {"type": "string"},
+            format_checker=self.Validator.FORMAT_CHECKER,
+            _resolver=new._resolver,
+        )
+
+        self.assertEqual(new, expected)
+        self.assertNotEqual(new, original)
+
+    def test_evolve_with_subclass(self):
+        """
+        Subclassing validators isn't supported public API, but some users have
+        done it, because we don't actually error entirely when it's done :/
+
+        We need to deprecate doing so first to help as many of these users
+        ensure they can move to supported APIs, but this test ensures that in
+        the interim, we haven't broken those users.
+        """
+
+        with self.assertWarns(DeprecationWarning):
+            @define
+            class OhNo(self.Validator):
+                foo = field(factory=lambda: [1, 2, 3])
+                _bar = field(default=37)
+
+        validator = OhNo({}, bar=12)
+        self.assertEqual(validator.foo, [1, 2, 3])
+
+        new = validator.evolve(schema={"type": "integer"})
+        self.assertEqual(new.foo, [1, 2, 3])
+        self.assertEqual(new._bar, 12)
+
+    def test_is_type_is_true_for_valid_type(self):
+        self.assertTrue(self.Validator({}).is_type("foo", "string"))
+
+    def test_is_type_is_false_for_invalid_type(self):
+        self.assertFalse(self.Validator({}).is_type("foo", "array"))
+
+    def test_is_type_evades_bool_inheriting_from_int(self):
+        self.assertFalse(self.Validator({}).is_type(True, "integer"))
+        self.assertFalse(self.Validator({}).is_type(True, "number"))
+
+    def test_it_can_validate_with_decimals(self):
+        schema = {"items": {"type": "number"}}
+        Validator = validators.extend(
+            self.Validator,
+            type_checker=self.Validator.TYPE_CHECKER.redefine(
+                "number",
+                lambda checker, thing: isinstance(
+                    thing, (int, float, Decimal),
+                ) and not isinstance(thing, bool),
+            ),
+        )
+
+        validator = Validator(schema)
+        validator.validate([1, 1.1, Decimal(1) / Decimal(8)])
+
+        invalid = ["foo", {}, [], True, None]
+        self.assertEqual(
+            [error.instance for error in validator.iter_errors(invalid)],
+            invalid,
+        )
+
+    def test_it_returns_true_for_formats_it_does_not_know_about(self):
+        validator = self.Validator(
+            {"format": "carrot"}, format_checker=FormatChecker(),
+        )
+        validator.validate("bugs")
+
+    def test_it_does_not_validate_formats_by_default(self):
+        validator = self.Validator({})
+        self.assertIsNone(validator.format_checker)
+
+    def test_it_validates_formats_if_a_checker_is_provided(self):
+        checker = FormatChecker()
+        bad = ValueError("Bad!")
+
+        @checker.checks("foo", raises=ValueError)
+        def check(value):
+            if value == "good":
+                return True
+            elif value == "bad":
+                raise bad
+            else:  # pragma: no cover
+                self.fail(f"What is {value}? [Baby Don't Hurt Me]")
+
+        validator = self.Validator(
+            {"format": "foo"}, format_checker=checker,
+        )
+
+        validator.validate("good")
+        with self.assertRaises(exceptions.ValidationError) as cm:
+            validator.validate("bad")
+
+        # Make sure original cause is attached
+        self.assertIs(cm.exception.cause, bad)
+
+    def test_non_string_custom_type(self):
+        non_string_type = object()
+        schema = {"type": [non_string_type]}
+        Crazy = validators.extend(
+            self.Validator,
+            type_checker=self.Validator.TYPE_CHECKER.redefine(
+                non_string_type,
+                lambda checker, thing: isinstance(thing, int),
+            ),
+        )
+        Crazy(schema).validate(15)
+
+    def test_it_properly_formats_tuples_in_errors(self):
+        """
+        A tuple instance properly formats validation errors for uniqueItems.
+
+        See #224
+        """
+        TupleValidator = validators.extend(
+            self.Validator,
+            type_checker=self.Validator.TYPE_CHECKER.redefine(
+                "array",
+                lambda checker, thing: isinstance(thing, tuple),
+            ),
+        )
+        with self.assertRaises(exceptions.ValidationError) as e:
+            TupleValidator({"uniqueItems": True}).validate((1, 1))
+        self.assertIn("(1, 1) has non-unique elements", str(e.exception))
+
+    def test_check_redefined_sequence(self):
+        """
+        Allow array to validate against another defined sequence type
+        """
+        schema = {"type": "array", "uniqueItems": True}
+        MyMapping = namedtuple("MyMapping", "a, b")
+        Validator = validators.extend(
+            self.Validator,
+            type_checker=self.Validator.TYPE_CHECKER.redefine_many(
+                {
+                    "array": lambda checker, thing: isinstance(
+                        thing, (list, deque),
+                    ),
+                    "object": lambda checker, thing: isinstance(
+                        thing, (dict, MyMapping),
+                    ),
+                },
+            ),
+        )
+        validator = Validator(schema)
+
+        valid_instances = [
+            deque(["a", None, "1", "", True]),
+            deque([[False], [0]]),
+            [deque([False]), deque([0])],
+            [[deque([False])], [deque([0])]],
+            [[[[[deque([False])]]]], [[[[deque([0])]]]]],
+            [deque([deque([False])]), deque([deque([0])])],
+            [MyMapping("a", 0), MyMapping("a", False)],
+            [
+                MyMapping("a", [deque([0])]),
+                MyMapping("a", [deque([False])]),
+            ],
+            [
+                MyMapping("a", [MyMapping("a", deque([0]))]),
+                MyMapping("a", [MyMapping("a", deque([False]))]),
+            ],
+            [deque(deque(deque([False]))), deque(deque(deque([0])))],
+        ]
+
+        for instance in valid_instances:
+            validator.validate(instance)
+
+        invalid_instances = [
+            deque(["a", "b", "a"]),
+            deque([[False], [False]]),
+            [deque([False]), deque([False])],
+            [[deque([False])], [deque([False])]],
+            [[[[[deque([False])]]]], [[[[deque([False])]]]]],
+            [deque([deque([False])]), deque([deque([False])])],
+            [MyMapping("a", False), MyMapping("a", False)],
+            [
+                MyMapping("a", [deque([False])]),
+                MyMapping("a", [deque([False])]),
+            ],
+            [
+                MyMapping("a", [MyMapping("a", deque([False]))]),
+                MyMapping("a", [MyMapping("a", deque([False]))]),
+            ],
+            [deque(deque(deque([False]))), deque(deque(deque([False])))],
+        ]
+
+        for instance in invalid_instances:
+            with self.assertRaises(exceptions.ValidationError):
+                validator.validate(instance)
+
+    def test_it_creates_a_ref_resolver_if_not_provided(self):
+        with self.assertWarns(DeprecationWarning):
+            resolver = self.Validator({}).resolver
+        self.assertIsInstance(resolver, validators._RefResolver)
+
+    def test_it_upconverts_from_deprecated_RefResolvers(self):
+        ref, schema = "someCoolRef", {"type": "integer"}
+        resolver = validators._RefResolver("", {}, store={ref: schema})
+        validator = self.Validator({"$ref": ref}, resolver=resolver)
+
+        with self.assertRaises(exceptions.ValidationError):
+            validator.validate(None)
+
+    def test_it_upconverts_from_yet_older_deprecated_legacy_RefResolvers(self):
+        """
+        Legacy RefResolvers support only the context manager form of
+        resolution.
+        """
+
+        class LegacyRefResolver:
+            @contextmanager
+            def resolving(this, ref):
+                self.assertEqual(ref, "the ref")
+                yield {"type": "integer"}
+
+        resolver = LegacyRefResolver()
+        schema = {"$ref": "the ref"}
+
+        with self.assertRaises(exceptions.ValidationError):
+            self.Validator(schema, resolver=resolver).validate(None)
+
+
+class AntiDraft6LeakMixin:
+    """
+    Make sure functionality from draft 6 doesn't leak backwards in time.
+    """
+
+    def test_True_is_not_a_schema(self):
+        with self.assertRaises(exceptions.SchemaError) as e:
+            self.Validator.check_schema(True)
+        self.assertIn("True is not of type", str(e.exception))
+
+    def test_False_is_not_a_schema(self):
+        with self.assertRaises(exceptions.SchemaError) as e:
+            self.Validator.check_schema(False)
+        self.assertIn("False is not of type", str(e.exception))
+
+    def test_True_is_not_a_schema_even_if_you_forget_to_check(self):
+        with self.assertRaises(Exception) as e:
+            self.Validator(True).validate(12)
+        self.assertNotIsInstance(e.exception, exceptions.ValidationError)
+
+    def test_False_is_not_a_schema_even_if_you_forget_to_check(self):
+        with self.assertRaises(Exception) as e:
+            self.Validator(False).validate(12)
+        self.assertNotIsInstance(e.exception, exceptions.ValidationError)
+
+
+class TestDraft3Validator(AntiDraft6LeakMixin, ValidatorTestMixin, TestCase):
+    Validator = validators.Draft3Validator
+    valid: tuple[dict, dict] = ({}, {})
+    invalid = {"type": "integer"}, "foo"
+
+    def test_any_type_is_valid_for_type_any(self):
+        validator = self.Validator({"type": "any"})
+        validator.validate(object())
+
+    def test_any_type_is_redefinable(self):
+        """
+        Sigh, because why not.
+        """
+        Crazy = validators.extend(
+            self.Validator,
+            type_checker=self.Validator.TYPE_CHECKER.redefine(
+                "any", lambda checker, thing: isinstance(thing, int),
+            ),
+        )
+        validator = Crazy({"type": "any"})
+        validator.validate(12)
+        with self.assertRaises(exceptions.ValidationError):
+            validator.validate("foo")
+
+    def test_is_type_is_true_for_any_type(self):
+        self.assertTrue(self.Validator({"type": "any"}).is_valid(object()))
+
+    def test_is_type_does_not_evade_bool_if_it_is_being_tested(self):
+        self.assertTrue(self.Validator({}).is_type(True, "boolean"))
+        self.assertTrue(self.Validator({"type": "any"}).is_valid(True))
+
+
+class TestDraft4Validator(AntiDraft6LeakMixin, ValidatorTestMixin, TestCase):
+    Validator = validators.Draft4Validator
+    valid: tuple[dict, dict] = ({}, {})
+    invalid = {"type": "integer"}, "foo"
+
+
+class TestDraft6Validator(ValidatorTestMixin, TestCase):
+    Validator = validators.Draft6Validator
+    valid: tuple[dict, dict] = ({}, {})
+    invalid = {"type": "integer"}, "foo"
+
+
+class TestDraft7Validator(ValidatorTestMixin, TestCase):
+    Validator = validators.Draft7Validator
+    valid: tuple[dict, dict] = ({}, {})
+    invalid = {"type": "integer"}, "foo"
+
+
+class TestDraft201909Validator(ValidatorTestMixin, TestCase):
+    Validator = validators.Draft201909Validator
+    valid: tuple[dict, dict] = ({}, {})
+    invalid = {"type": "integer"}, "foo"
+
+
+class TestDraft202012Validator(ValidatorTestMixin, TestCase):
+    Validator = validators.Draft202012Validator
+    valid: tuple[dict, dict] = ({}, {})
+    invalid = {"type": "integer"}, "foo"
+
+
+class TestLatestValidator(TestCase):
+    """
+    These really apply to multiple versions but are easiest to test on one.
+    """
+
+    def test_ref_resolvers_may_have_boolean_schemas_stored(self):
+        ref = "someCoolRef"
+        schema = {"$ref": ref}
+        resolver = validators._RefResolver("", {}, store={ref: False})
+        validator = validators._LATEST_VERSION(schema, resolver=resolver)
+
+        with self.assertRaises(exceptions.ValidationError):
+            validator.validate(None)
+
+
+class TestValidatorFor(TestCase):
+    def test_draft_3(self):
+        schema = {"$schema": "http://json-schema.org/draft-03/schema"}
+        self.assertIs(
+            validators.validator_for(schema),
+            validators.Draft3Validator,
+        )
+
+        schema = {"$schema": "http://json-schema.org/draft-03/schema#"}
+        self.assertIs(
+            validators.validator_for(schema),
+            validators.Draft3Validator,
+        )
+
+    def test_draft_4(self):
+        schema = {"$schema": "http://json-schema.org/draft-04/schema"}
+        self.assertIs(
+            validators.validator_for(schema),
+            validators.Draft4Validator,
+        )
+
+        schema = {"$schema": "http://json-schema.org/draft-04/schema#"}
+        self.assertIs(
+            validators.validator_for(schema),
+            validators.Draft4Validator,
+        )
+
+    def test_draft_6(self):
+        schema = {"$schema": "http://json-schema.org/draft-06/schema"}
+        self.assertIs(
+            validators.validator_for(schema),
+            validators.Draft6Validator,
+        )
+
+        schema = {"$schema": "http://json-schema.org/draft-06/schema#"}
+        self.assertIs(
+            validators.validator_for(schema),
+            validators.Draft6Validator,
+        )
+
+    def test_draft_7(self):
+        schema = {"$schema": "http://json-schema.org/draft-07/schema"}
+        self.assertIs(
+            validators.validator_for(schema),
+            validators.Draft7Validator,
+        )
+
+        schema = {"$schema": "http://json-schema.org/draft-07/schema#"}
+        self.assertIs(
+            validators.validator_for(schema),
+            validators.Draft7Validator,
+        )
+
+    def test_draft_201909(self):
+        schema = {"$schema": "https://json-schema.org/draft/2019-09/schema"}
+        self.assertIs(
+            validators.validator_for(schema),
+            validators.Draft201909Validator,
+        )
+
+        schema = {"$schema": "https://json-schema.org/draft/2019-09/schema#"}
+        self.assertIs(
+            validators.validator_for(schema),
+            validators.Draft201909Validator,
+        )
+
+    def test_draft_202012(self):
+        schema = {"$schema": "https://json-schema.org/draft/2020-12/schema"}
+        self.assertIs(
+            validators.validator_for(schema),
+            validators.Draft202012Validator,
+        )
+
+        schema = {"$schema": "https://json-schema.org/draft/2020-12/schema#"}
+        self.assertIs(
+            validators.validator_for(schema),
+            validators.Draft202012Validator,
+        )
+
+    def test_True(self):
+        self.assertIs(
+            validators.validator_for(True),
+            validators._LATEST_VERSION,
+        )
+
+    def test_False(self):
+        self.assertIs(
+            validators.validator_for(False),
+            validators._LATEST_VERSION,
+        )
+
+    def test_custom_validator(self):
+        Validator = validators.create(
+            meta_schema={"id": "meta schema id"},
+            version="12",
+            id_of=lambda s: s.get("id", ""),
+        )
+        schema = {"$schema": "meta schema id"}
+        self.assertIs(
+            validators.validator_for(schema),
+            Validator,
+        )
+
+    def test_custom_validator_draft6(self):
+        Validator = validators.create(
+            meta_schema={"$id": "meta schema $id"},
+            version="13",
+        )
+        schema = {"$schema": "meta schema $id"}
+        self.assertIs(
+            validators.validator_for(schema),
+            Validator,
+        )
+
+    def test_validator_for_jsonschema_default(self):
+        self.assertIs(validators.validator_for({}), validators._LATEST_VERSION)
+
+    def test_validator_for_custom_default(self):
+        self.assertIs(validators.validator_for({}, default=None), None)
+
+    def test_warns_if_meta_schema_specified_was_not_found(self):
+        with self.assertWarns(DeprecationWarning) as cm:
+            validators.validator_for(schema={"$schema": "unknownSchema"})
+
+        self.assertEqual(cm.filename, __file__)
+        self.assertEqual(
+            str(cm.warning),
+            "The metaschema specified by $schema was not found. "
+            "Using the latest draft to validate, but this will raise "
+            "an error in the future.",
+        )
+
+    def test_does_not_warn_if_meta_schema_is_unspecified(self):
+        with warnings.catch_warnings(record=True) as w:
+            warnings.simplefilter("always")
+            validators.validator_for(schema={}, default={})
+        self.assertFalse(w)
+
+    def test_validator_for_custom_default_with_schema(self):
+        schema, default = {"$schema": "mailto:foo@example.com"}, object()
+        self.assertIs(validators.validator_for(schema, default), default)
+
+
+class TestValidate(TestCase):
+    def assertUses(self, schema, Validator):
+        result = []
+        with mock.patch.object(Validator, "check_schema", result.append):
+            validators.validate({}, schema)
+        self.assertEqual(result, [schema])
+
+    def test_draft3_validator_is_chosen(self):
+        self.assertUses(
+            schema={"$schema": "http://json-schema.org/draft-03/schema#"},
+            Validator=validators.Draft3Validator,
+        )
+        # Make sure it works without the empty fragment
+        self.assertUses(
+            schema={"$schema": "http://json-schema.org/draft-03/schema"},
+            Validator=validators.Draft3Validator,
+        )
+
+    def test_draft4_validator_is_chosen(self):
+        self.assertUses(
+            schema={"$schema": "http://json-schema.org/draft-04/schema#"},
+            Validator=validators.Draft4Validator,
+        )
+        # Make sure it works without the empty fragment
+        self.assertUses(
+            schema={"$schema": "http://json-schema.org/draft-04/schema"},
+            Validator=validators.Draft4Validator,
+        )
+
+    def test_draft6_validator_is_chosen(self):
+        self.assertUses(
+            schema={"$schema": "http://json-schema.org/draft-06/schema#"},
+            Validator=validators.Draft6Validator,
+        )
+        # Make sure it works without the empty fragment
+        self.assertUses(
+            schema={"$schema": "http://json-schema.org/draft-06/schema"},
+            Validator=validators.Draft6Validator,
+        )
+
+    def test_draft7_validator_is_chosen(self):
+        self.assertUses(
+            schema={"$schema": "http://json-schema.org/draft-07/schema#"},
+            Validator=validators.Draft7Validator,
+        )
+        # Make sure it works without the empty fragment
+        self.assertUses(
+            schema={"$schema": "http://json-schema.org/draft-07/schema"},
+            Validator=validators.Draft7Validator,
+        )
+
+    def test_draft202012_validator_is_chosen(self):
+        self.assertUses(
+            schema={
+                "$schema": "https://json-schema.org/draft/2020-12/schema#",
+            },
+            Validator=validators.Draft202012Validator,
+        )
+        # Make sure it works without the empty fragment
+        self.assertUses(
+            schema={
+                "$schema": "https://json-schema.org/draft/2020-12/schema",
+            },
+            Validator=validators.Draft202012Validator,
+        )
+
+    def test_draft202012_validator_is_the_default(self):
+        self.assertUses(schema={}, Validator=validators.Draft202012Validator)
+
+    def test_validation_error_message(self):
+        with self.assertRaises(exceptions.ValidationError) as e:
+            validators.validate(12, {"type": "string"})
+        self.assertRegex(
+            str(e.exception),
+            "(?s)Failed validating '.*' in schema.*On instance",
+        )
+
+    def test_schema_error_message(self):
+        with self.assertRaises(exceptions.SchemaError) as e:
+            validators.validate(12, {"type": 12})
+        self.assertRegex(
+            str(e.exception),
+            "(?s)Failed validating '.*' in metaschema.*On schema",
+        )
+
+    def test_it_uses_best_match(self):
+        schema = {
+            "oneOf": [
+                {"type": "number", "minimum": 20},
+                {"type": "array"},
+            ],
+        }
+        with self.assertRaises(exceptions.ValidationError) as e:
+            validators.validate(12, schema)
+        self.assertIn("12 is less than the minimum of 20", str(e.exception))
+
+
+class TestThreading(TestCase):
+    """
+    Threading-related functionality tests.
+
+    jsonschema doesn't promise thread safety, and its validation behavior
+    across multiple threads may change at any time, but that means it isn't
+    safe to share *validators* across threads, not that anytime one has
+    multiple threads that jsonschema won't work (it certainly is intended to).
+
+    These tests ensure that this minimal level of functionality continues to
+    work.
+    """
+
+    def test_validation_across_a_second_thread(self):
+        failed = []
+
+        def validate():
+            try:
+                validators.validate(instance=37, schema=True)
+            except:  # pragma: no cover  # noqa: E722
+                failed.append(sys.exc_info())
+
+        validate()  # just verify it succeeds
+
+        from threading import Thread
+        thread = Thread(target=validate)
+        thread.start()
+        thread.join()
+        self.assertEqual((thread.is_alive(), failed), (False, []))
+
+
+class TestReferencing(TestCase):
+    def test_registry_with_retrieve(self):
+        def retrieve(uri):
+            return DRAFT202012.create_resource({"type": "integer"})
+
+        registry = referencing.Registry(retrieve=retrieve)
+        schema = {"$ref": "https://example.com/"}
+        validator = validators.Draft202012Validator(schema, registry=registry)
+
+        self.assertEqual(
+            (validator.is_valid(12), validator.is_valid("foo")),
+            (True, False),
+        )
+
+    def test_custom_registries_do_not_autoretrieve_remote_resources(self):
+        registry = referencing.Registry()
+        schema = {"$ref": "https://example.com/"}
+        validator = validators.Draft202012Validator(schema, registry=registry)
+
+        with warnings.catch_warnings(record=True) as w:
+            warnings.simplefilter("always")
+            with self.assertRaises(referencing.exceptions.Unresolvable):
+                validator.validate(12)
+        self.assertFalse(w)
+
+
+class TestRefResolver(TestCase):
+
+    base_uri = ""
+    stored_uri = "foo://stored"
+    stored_schema = {"stored": "schema"}
+
+    def setUp(self):
+        self.referrer = {}
+        self.store = {self.stored_uri: self.stored_schema}
+        self.resolver = validators._RefResolver(
+            self.base_uri, self.referrer, self.store,
+        )
+
+    def test_it_does_not_retrieve_schema_urls_from_the_network(self):
+        ref = validators.Draft3Validator.META_SCHEMA["id"]
+        with mock.patch.object(self.resolver, "resolve_remote") as patched:  # noqa: SIM117
+            with self.resolver.resolving(ref) as resolved:
+                pass
+        self.assertEqual(resolved, validators.Draft3Validator.META_SCHEMA)
+        self.assertFalse(patched.called)
+
+    def test_it_resolves_local_refs(self):
+        ref = "#/properties/foo"
+        self.referrer["properties"] = {"foo": object()}
+        with self.resolver.resolving(ref) as resolved:
+            self.assertEqual(resolved, self.referrer["properties"]["foo"])
+
+    def test_it_resolves_local_refs_with_id(self):
+        schema = {"id": "http://bar/schema#", "a": {"foo": "bar"}}
+        resolver = validators._RefResolver.from_schema(
+            schema,
+            id_of=lambda schema: schema.get("id", ""),
+        )
+        with resolver.resolving("#/a") as resolved:
+            self.assertEqual(resolved, schema["a"])
+        with resolver.resolving("http://bar/schema#/a") as resolved:
+            self.assertEqual(resolved, schema["a"])
+
+    def test_it_retrieves_stored_refs(self):
+        with self.resolver.resolving(self.stored_uri) as resolved:
+            self.assertIs(resolved, self.stored_schema)
+
+        self.resolver.store["cached_ref"] = {"foo": 12}
+        with self.resolver.resolving("cached_ref#/foo") as resolved:
+            self.assertEqual(resolved, 12)
+
+    def test_it_retrieves_unstored_refs_via_requests(self):
+        ref = "http://bar#baz"
+        schema = {"baz": 12}
+
+        if "requests" in sys.modules:  # pragma: no cover
+            self.addCleanup(
+                sys.modules.__setitem__, "requests", sys.modules["requests"],
+            )
+        sys.modules["requests"] = ReallyFakeRequests({"http://bar": schema})
+
+        with self.resolver.resolving(ref) as resolved:
+            self.assertEqual(resolved, 12)
+
+    def test_it_retrieves_unstored_refs_via_urlopen(self):
+        ref = "http://bar#baz"
+        schema = {"baz": 12}
+
+        if "requests" in sys.modules:  # pragma: no cover
+            self.addCleanup(
+                sys.modules.__setitem__, "requests", sys.modules["requests"],
+            )
+        sys.modules["requests"] = None
+
+        @contextmanager
+        def fake_urlopen(url):
+            self.assertEqual(url, "http://bar")
+            yield BytesIO(json.dumps(schema).encode("utf8"))
+
+        self.addCleanup(setattr, validators, "urlopen", validators.urlopen)
+        validators.urlopen = fake_urlopen
+
+        with self.resolver.resolving(ref) as resolved:
+            pass
+        self.assertEqual(resolved, 12)
+
+    def test_it_retrieves_local_refs_via_urlopen(self):
+        with tempfile.NamedTemporaryFile(delete=False, mode="wt") as tempf:
+            self.addCleanup(os.remove, tempf.name)
+            json.dump({"foo": "bar"}, tempf)
+
+        ref = f"file://{pathname2url(tempf.name)}#foo"
+        with self.resolver.resolving(ref) as resolved:
+            self.assertEqual(resolved, "bar")
+
+    def test_it_can_construct_a_base_uri_from_a_schema(self):
+        schema = {"id": "foo"}
+        resolver = validators._RefResolver.from_schema(
+            schema,
+            id_of=lambda schema: schema.get("id", ""),
+        )
+        self.assertEqual(resolver.base_uri, "foo")
+        self.assertEqual(resolver.resolution_scope, "foo")
+        with resolver.resolving("") as resolved:
+            self.assertEqual(resolved, schema)
+        with resolver.resolving("#") as resolved:
+            self.assertEqual(resolved, schema)
+        with resolver.resolving("foo") as resolved:
+            self.assertEqual(resolved, schema)
+        with resolver.resolving("foo#") as resolved:
+            self.assertEqual(resolved, schema)
+
+    def test_it_can_construct_a_base_uri_from_a_schema_without_id(self):
+        schema = {}
+        resolver = validators._RefResolver.from_schema(schema)
+        self.assertEqual(resolver.base_uri, "")
+        self.assertEqual(resolver.resolution_scope, "")
+        with resolver.resolving("") as resolved:
+            self.assertEqual(resolved, schema)
+        with resolver.resolving("#") as resolved:
+            self.assertEqual(resolved, schema)
+
+    def test_custom_uri_scheme_handlers(self):
+        def handler(url):
+            self.assertEqual(url, ref)
+            return schema
+
+        schema = {"foo": "bar"}
+        ref = "foo://bar"
+        resolver = validators._RefResolver("", {}, handlers={"foo": handler})
+        with resolver.resolving(ref) as resolved:
+            self.assertEqual(resolved, schema)
+
+    def test_cache_remote_on(self):
+        response = [object()]
+
+        def handler(url):
+            try:
+                return response.pop()
+            except IndexError:  # pragma: no cover
+                self.fail("Response must not have been cached!")
+
+        ref = "foo://bar"
+        resolver = validators._RefResolver(
+            "", {}, cache_remote=True, handlers={"foo": handler},
+        )
+        with resolver.resolving(ref):
+            pass
+        with resolver.resolving(ref):
+            pass
+
+    def test_cache_remote_off(self):
+        response = [object()]
+
+        def handler(url):
+            try:
+                return response.pop()
+            except IndexError:  # pragma: no cover
+                self.fail("Handler called twice!")
+
+        ref = "foo://bar"
+        resolver = validators._RefResolver(
+            "", {}, cache_remote=False, handlers={"foo": handler},
+        )
+        with resolver.resolving(ref):
+            pass
+
+    def test_if_you_give_it_junk_you_get_a_resolution_error(self):
+        error = ValueError("Oh no! What's this?")
+
+        def handler(url):
+            raise error
+
+        ref = "foo://bar"
+        resolver = validators._RefResolver("", {}, handlers={"foo": handler})
+        with self.assertRaises(exceptions._RefResolutionError) as err:  # noqa: SIM117
+            with resolver.resolving(ref):
+                self.fail("Shouldn't get this far!")  # pragma: no cover
+        self.assertEqual(err.exception, exceptions._RefResolutionError(error))
+
+    def test_helpful_error_message_on_failed_pop_scope(self):
+        resolver = validators._RefResolver("", {})
+        resolver.pop_scope()
+        with self.assertRaises(exceptions._RefResolutionError) as exc:
+            resolver.pop_scope()
+        self.assertIn("Failed to pop the scope", str(exc.exception))
+
+    def test_pointer_within_schema_with_different_id(self):
+        """
+        See #1085.
+        """
+        schema = validators.Draft7Validator.META_SCHEMA
+        one = validators._RefResolver("", schema)
+        validator = validators.Draft7Validator(schema, resolver=one)
+        self.assertFalse(validator.is_valid({"maxLength": "foo"}))
+
+        another = {
+            "allOf": [{"$ref": validators.Draft7Validator.META_SCHEMA["$id"]}],
+        }
+        two = validators._RefResolver("", another)
+        validator = validators.Draft7Validator(another, resolver=two)
+        self.assertFalse(validator.is_valid({"maxLength": "foo"}))
+
+    def test_newly_created_validator_with_ref_resolver(self):
+        """
+        See https://github.com/python-jsonschema/jsonschema/issues/1061#issuecomment-1624266555.
+        """
+
+        def handle(uri):
+            self.assertEqual(uri, "http://example.com/foo")
+            return {"type": "integer"}
+
+        resolver = validators._RefResolver("", {}, handlers={"http": handle})
+        Validator = validators.create(
+            meta_schema={},
+            validators=validators.Draft4Validator.VALIDATORS,
+        )
+        schema = {"$id": "http://example.com/bar", "$ref": "foo"}
+        validator = Validator(schema, resolver=resolver)
+        self.assertEqual(
+            (validator.is_valid({}), validator.is_valid(37)),
+            (False, True),
+        )
+
+    def test_refresolver_with_pointer_in_schema_with_no_id(self):
+        """
+        See https://github.com/python-jsonschema/jsonschema/issues/1124#issuecomment-1632574249.
+        """
+
+        schema = {
+            "properties": {"x": {"$ref": "#/definitions/x"}},
+            "definitions": {"x": {"type": "integer"}},
+        }
+
+        validator = validators.Draft202012Validator(
+            schema,
+            resolver=validators._RefResolver("", schema),
+        )
+        self.assertEqual(
+            (validator.is_valid({"x": "y"}), validator.is_valid({"x": 37})),
+            (False, True),
+        )
+
+
+
+def sorted_errors(errors):
+    def key(error):
+        return (
+            [str(e) for e in error.path],
+            [str(e) for e in error.schema_path],
+        )
+    return sorted(errors, key=key)
+
+
+@define
+class ReallyFakeRequests:
+
+    _responses: dict[str, Any]
+
+    def get(self, url):
+        response = self._responses.get(url)
+        if url is None:  # pragma: no cover
+            raise ValueError("Unknown URL: " + repr(url))
+        return _ReallyFakeJSONResponse(json.dumps(response))
+
+
+@define
+class _ReallyFakeJSONResponse:
+
+    _response: str
+
+    def json(self):
+        return json.loads(self._response)