Specify expected outcome in a docstring as hexadecimal?

Question

Is there a way to specify expected integer outcomes in a docstring in hex notation?

def identity(val):
    """
    >>> identity(243)
    243
    >>> identity(243)
    0xf3
    """
    return val

if __name__ == "__main__":
    import doctest
    doctest.testmod()

Doctest doesn't interpret the hex notation, resulting in a failure:

**********************************************************************
File "hextest.py", line 5, in __main__.identity
Failed example:
    identity(243)
Expected:
    0xf3
Got:
    243
**********************************************************************
1 items had failures:
   1 of   2 in __main__.identity
***Test Failed*** 1 failures.

I'm aware that I could wrestle the docstring:

def identity(val):
    """
    >>> hex(identity(243))
    '0xf3'
    """
    return val

But it'd seem natural to have doctest understand literal integers in bases 8, 16 next to decimal.

Answer 1

Sure, you can write your own OutputChecker class to handle numbers however you want:

def identity(val):
    """
    >>> identity(243)
    0xf3
    >>> identity(243)
    243
    """

    return val


if __name__ == "__main__":
    import doctest

    OutputChecker = doctest.OutputChecker

    class HexOutputChecker(OutputChecker):

        def check_output(self, want, got, optionflags):

            if want.startswith('0x'):
                want_str = str(int(want, 16)) + '\n'
                return super().check_output(want_str, got, optionflags)
            else:
                return super().check_output(want, got, optionflags)

    doctest.OutputChecker = HexOutputChecker
    doctest.testmod(verbose=True)