using both debugger and Mock results in AttributeError

Question

I have a piece of unit tests code where at some place unittest.mock.Mock is used and I'd like to go through it step by step using debugger. I am using pdbpp, but it does not matter in this situation, standard pdb and ipdb fail on same issue. When debugger encounters Mock() call, whole process crashes with traceback below.

Example to replicate (simply run pytest bug_example.py and then use s (as step) for going through it).

My question is - why is it happening and if I am able to use both debugger and mock.

import unittest.mock


def function_that_uses_mock():
    mock = unittest.mock.Mock()
    # anything else
    foo = 42
    return foo


def test_something():
    breakpoint() # can be "import ipdb; ipdb.set_trace()" or anything else
    assert function_that_uses_mock() == 42
    # anything else

>       assert function_that_uses_mock() == 42

bug_example.py:13:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
bug_example.py:4: in function_that_uses_mock
    mock = unittest.mock.Mock()
/usr/lib/python3.10/unittest/mock.py:417: in __new__
    return instance
/usr/lib/python3.10/bdb.py:94: in trace_dispatch
    return self.dispatch_return(frame, arg)
/usr/lib/python3.10/bdb.py:153: in dispatch_return
    self.user_return(frame, arg)
/usr/lib/python3.10/pdb.py:294: in user_return
    self.interaction(frame, None)
/home/user/.local/lib/python3.10/site-packages/pdb.py:224: in interaction
    self.print_stack_entry(self.stack[self.curindex])
/home/user/.local/lib/python3.10/site-packages/pdb.py:893: in print_stack_entry
    print(self.format_stack_entry(frame_lineno, prompt_prefix), file=self.stdout)
/home/user/.local/lib/python3.10/site-packages/pdb.py:399: in format_stack_entry
    entry = super(Pdb, self).format_stack_entry(frame_lineno, lprefix)
/usr/lib/python3.10/bdb.py:572: in format_stack_entry
    s += reprlib.repr(rv)
/usr/lib/python3.10/reprlib.py:52: in repr
    return self.repr1(x, self.maxlevel)
/usr/lib/python3.10/reprlib.py:62: in repr1
    return self.repr_instance(x, level)
/usr/lib/python3.10/reprlib.py:143: in repr_instance
    return '<%s instance at %#x>' % (x.__class__.__name__, id(x))
/usr/lib/python3.10/unittest/mock.py:632: in __getattr__
    elif self._mock_methods is not None:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

self = <[AttributeError('_mock_methods') raised in repr()] Mock object at 0x7fe6115b1ba0>, name = '_mock_methods'

    def __getattr__(self, name):
        if name in {'_mock_methods', '_mock_unsafe'}:
>           raise AttributeError(name)
E           AttributeError: _mock_methods

/usr/lib/python3.10/unittest/mock.py:631: AttributeError

using both debugger and Mock results in AttributeError

0 Answers0