Format can apply to instances of any type.

Closes #125

Author: Julian

jsonschema/_validators.py

@@ -150,10 +150,7 @@ def pattern(validator, patrn, instance, schema):
 
 
 def format(validator, format, instance, schema):
-    if (
-        validator.format_checker is not None and
-        validator.is_type(instance, "string")
-    ):
+    if validator.format_checker is not None:
         try:
             validator.format_checker.check(instance, format)
         except FormatError as error:

jsonschema/tests/test_jsonschema_test_suite.py

@@ -180,6 +180,24 @@ def test_it_validates_formats_if_a_checker_is_provided(self):
         # Make sure original cause is attached
         self.assertIs(cm.exception.cause, cause)
 
+    def test_it_validates_formats_of_any_type(self):
+        checker = mock.Mock(spec=FormatChecker)
+        validator = self.validator_class(
+            {"format" : "foo"}, format_checker=checker,
+        )
+
+        validator.validate([1, 2, 3])
+
+        checker.check.assert_called_once_with([1, 2, 3], "foo")
+
+        cause = ValueError()
+        checker.check.side_effect = FormatError('aoeu', cause=cause)
+
+        with self.assertRaises(ValidationError) as cm:
+            validator.validate([1, 2, 3])
+        # Make sure original cause is attached
+        self.assertIs(cm.exception.cause, cause)
+
 
 @load_json_cases("draft3/*.json", ignore_glob="draft3/refRemote.json")
 @load_json_cases(