>>> from __future__ import print_function
>>> print (1,2)
1 2

in interactive session, but, with this 3 lines in tmp.txt:

python -m doctest tmp.txt 

fails (prints tuple)

Works for me in 2.7.8:

$ python --version
Python 2.7.8
# cat /tmp/test.py
#!/usr/bin/env python

from __future__ import print_function


def toto():
    """
    >>> print (42, 43)
    42 43
    """
    return 42
$ python -m doctest -v /tmp/test.py 
Trying:
    print (42, 43)
Expecting:
    42 43
ok
1 items had no tests:
    test
1 items passed all tests:
   1 tests in test.toto
1 tests in 2 items.
1 passed and 0 failed.
Test passed.

@Julien.Palard: There's a subtle difference between your test and the issue as written. Your test lives within a module and therefore executes testmodule (see https://hg.python.org/cpython/file/9f60d024e586/Lib/doctest.py#l1819) whereas the issue reported uses testfile (see https://hg.python.org/cpython/file/9f60d024e586/Lib/doctest.py#l1923). I believe the issue is that the __future__ import doesn't make it into compile (https://hg.python.org/cpython/file/9f60d024e586/Lib/doctest.py#l1314). I've been able to confirm the issue on 2.7 and that it's been resolved in 3.5. Unfortunately, I haven't had time to dig into this any further.

> it's been resolved in 3.5

Sorry, that statement can be a little misleading, possibly indicating that something may have changed in the doctest globals handling. It was resolved in 3.5 because print is no longer a statement so this ambiguous behaviour resolved by the print_function import no longer exists.