I could reproduce the problem on Fedora Core 5 with Python 2.4.3.

After tracing down the issue, I found the following:

The problem is in locate.py. There is a function called normalize defined in the locate.py file. This function is invoked by setlocale function if the incoming locale argument is not a string. (in your example this condition is true because locale.getlocale function returns a tuple so got variable is a tuple.) The normalize function is using an encoding_alias table which results to translate the full locale into an incorrect version. What happens in my environment is that there is an incoming value en_us.utf-8  which is converted to en_us.utf and that is the return value from normalize function. Then _setlocale low level function invoked in setlocale function throws an exception when it receives en_us.utf  argument and it is an unsupported locale setting.


This is the original code snippet in locale.py where it is converted in a wrong way in normalize function:


    # Second try: langname (without encoding)
    code = locale_alias.get(langname, None)
    if code is not None:
        if '.' in code:
            langname, defenc = code.split('.')
        else:
            langname = code
            defenc = ''
        if encoding:
            encoding = encoding_alias.get(encoding, encoding)
        else:
            encoding = defenc
        if encoding:
            return langname + '.' + encoding
        else:
            return langname

    else:
        return localename


To get it fixed, I modified the code in locate.py as follows:


    # Second try: langname (without encoding)
    code = locale_alias.get(langname, None)
    if code is not None:
        if '.' in code:
            langname, defenc = code.split('.')
        else:
            langname = code
            defenc = ''
#        if encoding:
#            encoding = encoding_alias.get(encoding, encoding)
#        else:
#            encoding = defenc
	if encoding is None:
	     encoding = defenc
        if encoding:
            return langname + '.' + encoding
        else:
            return langname

    else:
        return localename


So the effect of encoding_table is skipped. Then your test_locale.py returns OK.