classification
Title: doctest.DocTestFinder reports incorrect line numbers with exclude_empty=False
Type: Stage:
Components: Library (Lib) Versions: Python 3.5, Python 2.7
process
Status: open Resolution:
Dependencies: Superseder:
Assigned To: Nosy List: cpitclaudel, xtreak
Priority: normal Keywords:

Created on 2016-09-22 15:32 by cpitclaudel, last changed 2019-12-10 15:25 by xtreak.

Files
File name Uploaded Description Edit
example.py cpitclaudel, 2016-09-22 15:32
Messages (1)
msg277230 - (view) Author: Clément (cpitclaudel) Date: 2016-09-22 15:32
Line numbers reported by the doctest module are wrong when a function does not include a docstring.  With the attached example file, running

    python -c "import doctest, example; print(doctest.DocTestFinder(exclude_empty=False).find(example))"

produces

    [<DocTest example from example.py:5 (no examples)>,
     <DocTest example.a from example.py:5 (no examples)>,
     <DocTest example.b from example.py:5 (no examples)>,
     <DocTest example.c from example.py:None (no examples)>]

whereas if one uncomments the docstrings of a and c the output is

    [<DocTest example from example.py:1 (no examples)>,
     <DocTest example.a from example.py:1 (no examples)>,
     <DocTest example.b from example.py:5 (no examples)>,
     <DocTest example.c from example.py:9 (no examples)>]

This bug is due to this line in doctest:

    lineno = self._find_lineno(obj, source_lines)

The documentation of _find_lineno says this:

    def _find_lineno(self, obj, source_lines):
        """
        Return a line number of the given object's docstring.  Note:
        this method assumes that the object has a docstring.
        """

This assumption is violated by the call listed above, because of the exclude_empty=False parameter to DocTestFinder().

I guess lineno should just be None for all methods that do not have a docstring?
History
Date User Action Args
2019-12-10 15:25:39xtreaksetnosy: + xtreak
2016-09-22 15:32:20cpitclaudelcreate