Format project with black (#467)

Format with line length 110 to match flake8

make black part of linting check

Update travis spec for updated black requirements

Add diff output for black on failure

update changelog

vcr/serializers/compat.py

@@ -24,8 +24,8 @@ def convert_body_to_bytes(resp):
     http://pyyaml.org/wiki/PyYAMLDocumentation#Python3support
     """
     try:
-        if resp['body']['string'] is not None and not isinstance(resp['body']['string'], six.binary_type):
-            resp['body']['string'] = resp['body']['string'].encode('utf-8')
+        if resp["body"]["string"] is not None and not isinstance(resp["body"]["string"], six.binary_type):
+            resp["body"]["string"] = resp["body"]["string"].encode("utf-8")
     except (KeyError, TypeError, UnicodeEncodeError):
         # The thing we were converting either wasn't a dictionary or didn't
         # have the keys we were expecting.  Some of the tests just serialize
@@ -45,7 +45,7 @@ def _convert_string_to_unicode(string):
 
     try:
         if string is not None and not isinstance(string, six.text_type):
-            result = string.decode('utf-8')
+            result = string.decode("utf-8")
     except (TypeError, UnicodeDecodeError, AttributeError):
         # Sometimes the string actually is binary or StringIO object,
         # so if you can't decode it, just give up.
@@ -63,17 +63,15 @@ def convert_body_to_unicode(resp):
         # Some of the tests just serialize and deserialize a string.
         return _convert_string_to_unicode(resp)
     else:
-        body = resp.get('body')
+        body = resp.get("body")
 
         if body is not None:
             try:
-                body['string'] = _convert_string_to_unicode(
-                    body['string']
-                )
+                body["string"] = _convert_string_to_unicode(body["string"])
             except (KeyError, TypeError, AttributeError):
                 # The thing we were converting either wasn't a dictionary or
                 # didn't have the keys we were expecting.
                 # For example request object has no 'string' key.
-                resp['body'] = _convert_string_to_unicode(body)
+                resp["body"] = _convert_string_to_unicode(body)
 
     return resp

vcr/serializers/jsonserializer.py

@@ -23,7 +23,7 @@ def serialize(cassette_dict):
             b"Error serializing cassette to JSON",
             original.start,
             original.end,
-            original.args[-1] + error_message
+            original.args[-1] + error_message,
         )
     except TypeError:  # py3
         raise TypeError(error_message)