Merge branch 'master' into regex_value_validation

Author: manycoding

json/bin/jsonschema_suite

@@ -1,27 +1,14 @@
 #! /usr/bin/env python
 from __future__ import print_function
-import sys
-import textwrap
-
-try:
-    import argparse
-except ImportError:
-    print(textwrap.dedent("""
-        The argparse library could not be imported. jsonschema_suite requires
-        either Python 2.7 or for you to install argparse. You can do so by
-        running `pip install argparse`, `easy_install argparse` or by
-        downloading argparse and running `python2.6 setup.py install`.
-
-        See https://pypi.python.org/pypi/argparse for details.
-    """.strip("\n")))
-    sys.exit(1)
-
+import argparse
 import errno
 import fnmatch
 import json
 import os
 import random
 import shutil
+import sys
+import textwrap
 import unittest
 import warnings
 

jsonschema/tests/test_validators.py

@@ -1119,7 +1119,7 @@ def test(self, format=format):
     setattr(TestBuiltinFormats, name, test)
 
 
-class TestValidatorFor(TestCase):
+class TestValidatorFor(SynchronousTestCase):
     def test_draft_3(self):
         schema = {"$schema": "http://json-schema.org/draft-03/schema"}
         self.assertIs(
@@ -1213,6 +1213,26 @@ def test_validator_for_jsonschema_default(self):
     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):
+        self.assertWarns(
+            category=DeprecationWarning,
+            message=(
+                "The metaschema specified by $schema was not found. "
+                "Using the latest draft to validate, but this will raise "
+                "an error in the future."
+            ),
+            # https://tm.tl/9363 :'(
+            filename=sys.modules[self.assertWarns.__module__].__file__,
+
+            f=validators.validator_for,
+            schema={u"$schema": "unknownSchema"},
+            default={},
+        )
+
+    def test_does_not_warn_if_meta_schema_is_unspecified(self):
+        validators.validator_for(schema={}, default={}),
+        self.assertFalse(self.flushWarnings())
+
 
 class TestValidate(TestCase):
     def assertUses(self, schema, Validator):

jsonschema/validators.py

@@ -187,6 +187,10 @@ def create(
             will be converted to functions and redefined in this object's
             `jsonschema.TypeChecker`.
 
+        id_of (callable):
+
+            A function that given a schema, returns its ID.
+
     Returns:
 
         a new `jsonschema.IValidator` class
@@ -895,6 +899,16 @@ def validator_for(schema, default=_LATEST_VERSION):
             If unprovided, the default is to return
             the latest supported draft.
     """
-    if schema is True or schema is False:
+    if schema is True or schema is False or u"$schema" not in schema:
         return default
-    return meta_schemas.get(schema.get(u"$schema", u""), default)
+    if schema[u"$schema"] not in meta_schemas:
+        warn(
+            (
+                "The metaschema specified by $schema was not found. "
+                "Using the latest draft to validate, but this will raise "
+                "an error in the future."
+            ),
+            DeprecationWarning,
+            stacklevel=2,
+        )
+    return meta_schemas.get(schema[u"$schema"], _LATEST_VERSION)