2to3 follow-up: clean the rough edges wrt. text/data cut in tests
    
    Previous " 2to3: PY3 distinguishes text (abstract type) and data
    (raw bytes)" commit (possibly with other follow-ups on top) changes
    how some data are represented internally, and apparently it still
    causes issues in the test suite when run under Python 2.
    Hence to retain the compatibility, ensure the type match.
    
    Signed-off-by: Jan Pokorný <jpokorny@redhat.com>