pytest_assertion plugin: representation of details failed in pytest.approx AttributeError: 'tuple' object has no attribute 'expected'.

input:

import pytest


def sut():
    return [(1.0, 1.0)]


def test_approx():
    assert sut() == pytest.approx([(2.0, 2.0)])

output:

===================== test session starts ======================
platform darwin -- Python 3.12.6, pytest-8.3.3, pluggy-1.5.0
rootdir: /Users/thomas/projects/demo_assertion
collected 1 item

test_approx.py F                                         [100%]

=========================== FAILURES ===========================
_________________________ test_approx __________________________

    def test_approx():
>       assert sut() == pytest.approx([(2.0, 2.0)])
E       AssertionError: assert [(1.0, 1.0)] == approx([(2.0, 2.0)])
E
E         (pytest_assertion plugin: representation of details failed: /Users/thomas/.virtualenvs/demo_assertion/lib/python3.12/site-packages/_pytest/python_api.py:343: AttributeError: 'tuple' object has no attribute 'expected'.
E          Probably an object has a faulty __repr__.)

test_approx.py:9: AssertionError
=================== short test summary info ====================
FAILED test_approx.py::test_approx - AssertionError: assert [(1.0, 1.0)] == approx([(2.0, 2.0)])
====================== 1 failed in 0.01s =======================

pip list:

Package   Version
--------- -------
iniconfig 2.0.0
packaging 24.1
pip       24.2
pluggy    1.5.0
pytest    8.3.3

uname -a: Darwin Thomass-MacBook-Pro.local 23.6.0 Darwin Kernel Version 23.6.0: Mon Jul 29 21:14:04 PDT 2024; root:xnu-10063.141.2~1/RELEASE_ARM64_T8122 arm64

• a detailed description of the bug or problem you are having
• output of pip list from the virtual environment you are using
• pytest and operating system versions
• minimal example if possible

Start by running the minimal test case with pytest 8.3.3, then inspect _pytest/python_api.py around line 343, where the reported AttributeError occurs. Trace the pytest.approx handling for a list of tuples and add or update a regression test for this input. Done means the assertion failure is reported without the plugin representation error.