Comment 2 for bug 1825867

py3 testcase fails coz of the change set proposed.
Considering a scenario for keystone.tests.unit.identity.backends.test_sql.TestIdentityDriver.test_authenticate_for_user_with_special_char with user_id='fl\xc3\xbcgel' (which actually is flügel, fl\xc3\xbcgel is the string representation in py2.)
In py3, as string/text means both ascii/unicode, fl\xc3\xbcgel as a user_id will mean flügel not mean flügel.

py3 console:
print ('fl\xc3\xbcgel') -> flügel
print (u'fl\xfcgel') -> flügel
bytes(u'fl\xfcgel', 'utf-8') = b'fl\xc3\xbcgel'
bytes('fl\xc3\xbcgel', 'utf-8') = b'fl\xc3\x83\xc2\xbcgel'

The string representation for flügel in py2 actually means flügel in string representation in py3. So, this unit test case might not be correct in the first place as user_id will not be 'fl\xc3\xbcgel' (can be this b'fl\xc3\xbcgel') when user is flügel.