sep.out

$ python3 sep.py 
different: cp037 b'a'
different: cp273 b'a'
different: cp424 b'a'
different: cp500 b'a'
different: cp875 b'a'
different: cp1026 b'a'
different: cp1140 b'a'
untested: cp65001
different: utf_32 b'\xff\xfe\x00\x00/\x00\x00\x00'
different: utf_32_be b'\x00\x00\x00/'
different: utf_32_le b'/\x00\x00\x00'
different: utf_16 b'\xff\xfe/\x00'
different: utf_16_be b'\x00/'
different: utf_16_le b'/\x00'
different: utf_8_sig b'\xef\xbb\xbf/'

sep.py

encodings = [
    'ascii',
    'big5',
    'big5hkscs',
    'cp037',
    'cp273',
    'cp424',
    'cp437',
    'cp500',
    'cp720',
    'cp737',
    'cp775',
    'cp850',
    'cp852',
    'cp855',
    'cp856',
    'cp857',
    'cp858',
    'cp860',
    'cp861',
    'cp862',
    'cp863',
    'cp864',
    'cp865',
    'cp866',
    'cp869',
    'cp874',
    'cp875',
    'cp932',
    'cp949',
    'cp950',
    'cp1006',
    'cp1026',
    'cp1125',
    'cp1140',
    'cp1250',
    'cp1251',
    'cp1252',
    'cp1253',
    'cp1254',
    'cp1255',
    'cp1256',
    'cp1257',
    'cp1258',
    'cp65001',
    'euc_jp',
    'euc_jis_2004',
    'euc_jisx0213',
    'euc_kr',
    'gb2312',
    'gbk',
    'gb18030',
    'hz',
    'iso2022_jp',
    'iso2022_jp_1',
    'iso2022_jp_2',
    'iso2022_jp_2004',
    'iso2022_jp_3',
    'iso2022_jp_ext',
    'iso2022_kr',
    'latin_1',
    'iso8859_2',
    'iso8859_3',
    'iso8859_4',
    'iso8859_5',
    'iso8859_6',
    'iso8859_7',
    'iso8859_8',
    'iso8859_9',
    'iso8859_10',
    'iso8859_11',
    'iso8859_13',
    'iso8859_14',
    'iso8859_15',
    'iso8859_16',
    'johab',
    'koi8_r',
    'koi8_t',
    'koi8_u',
    'kz1048',
    'mac_cyrillic',
    'mac_greek',
    'mac_iceland',
    'mac_latin2',
    'mac_roman',
    'mac_turkish',
    'ptcp154',
    'shift_jis',
    'shift_jis_2004',
    'shift_jisx0213',
    'utf_32',
    'utf_32_be',
    'utf_32_le',
    'utf_16',
    'utf_16_be',
    'utf_16_le',
    'utf_7',
    'utf_8',
    'utf_8_sig',
]

for encoding in encodings:
    try:
        encoded = u'/'.encode(encoding)
    except UnicodeEncodeError:
        print('unencodable:', encoding)
    except LookupError:
        print('untested:', encoding)
    else:
        if encoded != u'/'.encode('utf-8'):
            print('different:', encoding, encoded)