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, 3 insertions, 3 deletions

diff --git a/Lib/test/test_cmd_line_script.py b/Lib/test/test_cmd_line_script.py
index f10ab40..8f12b1e 100644
--- a/Lib/test/test_cmd_line_script.py
+++ b/Lib/test/test_cmd_line_script.py
@@ -400,7 +400,7 @@ class CmdLineTest(unittest.TestCase):
         # does not alter the value of sys.path[0]
         with os_helper.temp_dir() as script_dir:
             with os_helper.change_cwd(path=script_dir):
-                with open("-c", "w") as f:
+                with open("-c", "w", encoding="utf-8") as f:
                     f.write("data")
                     rc, out, err = assert_python_ok('-c',
                         'import sys; print("sys.path[0]==%r" % sys.path[0])',
@@ -416,7 +416,7 @@ class CmdLineTest(unittest.TestCase):
         with os_helper.temp_dir() as script_dir:
             script_name = _make_test_script(script_dir, 'other')
             with os_helper.change_cwd(path=script_dir):
-                with open("-m", "w") as f:
+                with open("-m", "w", encoding="utf-8") as f:
                     f.write("data")
                     rc, out, err = assert_python_ok('-m', 'other', *example_args,
                                                     __isolated=False)
@@ -429,7 +429,7 @@ class CmdLineTest(unittest.TestCase):
         # will be failed.
         with os_helper.temp_dir() as script_dir:
             script_name = os.path.join(script_dir, "issue20884.py")
-            with open(script_name, "w", newline='\n') as f:
+            with open(script_name, "w", encoding="latin1", newline='\n') as f:
                 f.write("#coding: iso-8859-1\n")
                 f.write('"""\n')
                 for _ in range(30):