bpo-43510: Implement PEP 597 opt-in EncodingWarning. (GH-19481)
See [PEP 597](https://www.python.org/dev/peps/pep-0597/).
* Add `-X warn_default_encoding` and `PYTHONWARNDEFAULTENCODING`.
* Add EncodingWarning
* Add io.text_encoding()
* open(), TextIOWrapper() emits EncodingWarning when encoding is omitted and warn_default_encoding is enabled.
* _pyio.TextIOWrapper() uses UTF-8 as fallback default encoding used when failed to import locale module. (used during building Python)
* bz2, configparser, gzip, lzma, pathlib, tempfile modules use io.text_encoding().
* What's new entry
diff --git a/Lib/test/test_embed.py b/Lib/test/test_embed.py
index 6833b25..646cd06 100644
--- a/Lib/test/test_embed.py
+++ b/Lib/test/test_embed.py
@@ -389,6 +389,7 @@ class InitConfigTests(EmbeddingTestsMixin, unittest.TestCase):
'site_import': 1,
'bytes_warning': 0,
+ 'warn_default_encoding': 0,
'inspect': 0,
'interactive': 0,
'optimization_level': 0,