The test fails on Windows. Whereas on Unix, the two step commands produce this output:

-> print('1')
(Pdb) step
1
--Return--
> /net/pao/export/home/staff/loewis/work/33/bar.py(2)bar()->None
-> print('1')
(Pdb) step
--Return--
> /net/pao/export/home/staff/loewis/work/33/main.py(5)foo()->None
-> bar()
(Pdb) quit

on Windows, they produce this output:

-> print('1')
(Pdb) step
--Call--
> c:\users\martin\33\python\lib\encodings\cp850.py(18)encode()
-> def encode(self, input, final=False):
(Pdb) step
> c:\users\martin\33\python\lib\encodings\cp850.py(19)encode()
-> return codecs.charmap_encode(input,self.errors,encoding_map)[0]
(Pdb) quit

I.e. the stepping enters the print, and breaks in the codec.

Reopening the issue.