I attach tests.py file used to run the tests. Results are in python2.out.txt and python3.out.txt also attached.

> What are the results of os.stat(b'Русское имя') and os.stat(b'Русское имя') on Python 2.7 and Python 3.3+?

b'Русское имя' is not a valid syntax construct in Python 3 even though I have correct 'coding: utf-8' header and expect characters to be utf-8 bytes. Therefore I skipped this test for Python 3.
> python test.py
  File "tests.py", line 23
    print(os.stat(b'\u0420\u0443\u0441\u0441\u043a\u043e\u0435 \u0438\u043c\u044f'))
                   ^
SyntaxError: bytes can only contain ASCII literal characters.