bpo-43651: PEP 597: Fix EncodingWarning in some tests (GH-25145)

* test_asyncio
* test_bz2
* test_math
* test_cmath
* test_cmd_line
* test_cmd_line_script
* test_compile
* test_contextlib
* test_profile
* ctypes/test/test_find
* test_multiprocessing
* test_configparser
* test_csv
* test_dbm_dumb
* test_decimal
* test_difflib
* os.fdopen() calls io.text_encoding() to emit EncodingWarning for right place.

1 files changed, 4 insertions, 2 deletions

diff --git a/Lib/os.py b/Lib/os.py
index 05e9c32..ea09e8c 100644
--- a/Lib/os.py
+++ b/Lib/os.py
@@ -1020,11 +1020,13 @@ if sys.platform != 'vxworks':
     __all__.append("popen")
 
 # Supply os.fdopen()
-def fdopen(fd, *args, **kwargs):
+def fdopen(fd, mode="r", buffering=-1, encoding=None, *args, **kwargs):
     if not isinstance(fd, int):
         raise TypeError("invalid fd type (%s, expected integer)" % type(fd))
     import io
-    return io.open(fd, *args, **kwargs)
+    if "b" not in mode:
+        encoding = io.text_encoding(encoding)
+    return io.open(fd, mode, buffering, encoding, *args, **kwargs)
 
 
 # For testing purposes, make sure the function is available when the C