python-jsonschema#708 - move _json_formatter from _PrettyFormatter

As per code review discussion.

Author: sloanlance

jsonschema/cli.py

@@ -66,17 +66,17 @@ def validation_success(self, **kwargs):
         self._stdout.write(self._formatter.validation_success(**kwargs))
 
 
+def _json_formatter(x):
+    return json.dumps(x, indent=4, sort_keys=True)
+
+
 @attr.s
 class _PrettyFormatter(object):
     _MESSAGE_BAR_CHAR = "═"
     _MESSAGE_CORNER_CHARS = "╒", "╕"
     _MESSAGE_FORMAT = "{}══[{}]═══({})"
     _MESSAGE_MAX_LENGTH = 79
 
-    @classmethod
-    def _json_formatter(cls, x):
-        return json.dumps(x, indent=4, sort_keys=True)
-
     def _message_line(self, path, type, header=False):
         begin_char, end_char = self._MESSAGE_CORNER_CHARS if header \
             else [self._MESSAGE_BAR_CHAR] * 2
@@ -112,7 +112,7 @@ def validation_error(self, instance_path, error):
         return self._error_msg(
             path=instance_path,
             type=error.__class__.__name__,
-            body=error._formatted_message(formatter=self._json_formatter),
+            body=error._formatted_message(formatter=_json_formatter),
         )
 
     def validation_success(self, instance_path):

jsonschema/tests/test_cli.py

@@ -310,7 +310,7 @@ def test_invalid_schema_pretty_output(self):
         with self.assertRaises(SchemaError) as e:
             validate(schema=schema, instance="")
         error = str(e.exception._formatted_message(
-            formatter=cli._PrettyFormatter._json_formatter))
+            formatter=cli._json_formatter))
 
         self.assertOutputs(
             files=dict(some_schema=json.dumps(schema)),
@@ -341,7 +341,7 @@ def test_invalid_schema_multiple_errors_pretty_output(self):
         with self.assertRaises(SchemaError) as e:
             validate(schema=schema, instance="")
         error = str(e.exception._formatted_message(
-            formatter=cli._PrettyFormatter._json_formatter))
+            formatter=cli._json_formatter))
 
         self.assertOutputs(
             files=dict(some_schema=json.dumps(schema)),
@@ -379,7 +379,7 @@ def test_invalid_schema_with_invalid_instance_pretty_output(self):
         with self.assertRaises(SchemaError) as e:
             validate(schema=schema, instance=instance)
         error = str(e.exception._formatted_message(
-            formatter=cli._PrettyFormatter._json_formatter))
+            formatter=cli._json_formatter))
 
         self.assertOutputs(
             files=dict(