doctest expecting asserts behaves differently than stdlib

[isidroas]

The following file,

import math

def square_root(n):
    """
    >>> square_root(4)
    2.0

    >>> square_root(-1)
    Traceback (most recent call last):
        ...
    AssertionError: number must not be negative

    """
    assert n>= 0, 'number must not be negative'
    return math.sqrt(n)

works well with the doctest of stdlib,

$ python -m doctest test.py

$ echo $?
0

but it fails using pytest:

$ python -m doctest test.py
$ pytest --doctest-modules test.py
============================= test session starts ==============================
platform linux -- Python 3.11.6, pytest-8.2.1, pluggy-1.5.0
rootdir: /tmp
collected 1 item

test.py F                                                                [100%]

=================================== FAILURES ===================================
__________________________ [doctest] test.square_root __________________________
004 
005     >>> square_root(4)
006     2.0
007 
008     >>> square_root(-1)
Differences (unified diff with -expected +actual):
    @@ -1,3 +1,9 @@
     Traceback (most recent call last):
    -    ...
    +  File "/usr/lib/python3.11/doctest.py", line 1351, in __run
    +    exec(compile(example.source, filename, "single",
    +  File "<doctest test.square_root[1]>", line 1, in <module>
    +    square_root(-1)
    +  File "/tmp/test.py", line 14, in square_root
    +    assert n>= 0, 'number must not be negative'
     AssertionError: number must not be negative
    +assert -1 >= 0

/tmp/test.py:8: DocTestFailure
=========================== short test summary info ============================
FAILED test.py::test.square_root
============================== 1 failed in 0.01s ===============================

due to that assert -1 >= 0 extra line

[shannoncai]

I can take a look into this issue! I'll create a pull request soon but let me know if there's anything else.