$ LC_ALL=uk_UA.koi8u ./python -m test Traceback (most recent call last): File "<frozen runpy>", line 198, in _run_module_as_main File "<frozen runpy>", line 88, in _run_code File "/home/serhiy/py/cpython/Lib/test/__main__.py", line 2, in <module> main() ^^^^^^ File "/home/serhiy/py/cpython/Lib/test/libregrtest/main.py", line 737, in main Regrtest().main(tests=tests, **kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/serhiy/py/cpython/Lib/contextlib.py", line 155, in __exit__ self.gen.throw(typ, value, traceback) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/serhiy/py/cpython/Lib/contextlib.py", line 155, in __exit__ self.gen.throw(typ, value, traceback) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/serhiy/py/cpython/Lib/test/support/os_helper.py", line 396, in temp_dir yield path ^^^^^^^^^^ File "/home/serhiy/py/cpython/Lib/contextlib.py", line 155, in __exit__ self.gen.throw(typ, value, traceback) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/serhiy/py/cpython/Lib/test/support/os_helper.py", line 427, in change_cwd yield os.getcwd() ^^^^^^^^^^^^^^^^^ File "/home/serhiy/py/cpython/Lib/test/support/os_helper.py", line 449, in temp_cwd yield cwd_dir ^^^^^^^^^^^^^ File "/home/serhiy/py/cpython/Lib/test/libregrtest/main.py", line 675, in main self._main(tests, kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/serhiy/py/cpython/Lib/test/libregrtest/main.py", line 704, in _main setup_tests(self.ns) ^^^^^^^^^^^^^^^^^^^^ File "/home/serhiy/py/cpython/Lib/test/libregrtest/setup.py", line 107, in setup_tests os.environ.setdefault( ^^^^^^^^^^^^^^^^^^^^^^ File "<frozen os>", line 717, in setdefault File "<frozen os>", line 683, in __setitem__ File "<frozen os>", line 758, in encode File "/home/serhiy/py/cpython/Lib/encodings/koi8_u.py", line 12, in encode return codecs.charmap_encode(input,errors,encoding_table) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ UnicodeEncodeError: 'charmap' codec can't encode character '\U0001f60e' in position 0: character maps to <undefined>