Fix test_it_validates_formats_by_default

Author: manycoding

jsonschema/tests/test_validators.py

@@ -993,7 +993,7 @@ def test_it_returns_true_for_formats_it_does_not_know_about(self):
 
     def test_it_validates_formats_by_default(self):
         validator = self.Validator({})
-        self.assertIsInstance(validator.format_checker, FormatChecker())
+        self.assertIsInstance(validator.format_checker, FormatChecker)
 
     def test_it_validates_formats_if_a_checker_is_provided(self):
         checker = FormatChecker()