Prefer builtin open() over io.open() and codecs.open()

In Python3, the functions io.open() is an alias of the builtin open()
and codecs.open() is functionally equivalent. To reduce indirection,
number of imports, and number of patterns, always prefer the builtin.

https://docs.python.org/3/library/io.html#high-level-module-interface

> io.open()
>
> This is an alias for the builtin open() function.

1 files changed, 2 insertions, 3 deletions

diff --git a/sphinx/testing/path.py b/sphinx/testing/path.py
index 585933499..6deda345f 100644
--- a/sphinx/testing/path.py
+++ b/sphinx/testing/path.py
@@ -9,7 +9,6 @@
 import os
 import shutil
 import sys
-from io import open
 
 from six import PY2, text_type
 
@@ -161,7 +160,7 @@ class path(text_type):
         """
         if isinstance(text, bytes):
             text = text.decode(encoding)
-        with open(self, 'w', encoding=encoding, **kwargs) as f:
+        with open(self, 'w', encoding=encoding, **kwargs) as f:  # type: ignore
             f.write(text)
 
     def text(self, encoding='utf-8', **kwargs):
@@ -170,7 +169,7 @@ class path(text_type):
         Returns the text in the file.
         """
         mode = 'rU' if PY2 else 'r'
-        with open(self, mode=mode, encoding=encoding, **kwargs) as f:
+        with open(self, mode=mode, encoding=encoding, **kwargs) as f:  # type: ignore
             return f.read()
 
     def bytes(self):