ModuleNotFoundError for Numpy when pytest.approx fails #9726
Description
Description of the bug:
When using pytest.approx to compare lists in a test, a ModuleNotFoundError is raised for Numpy whenever the test fails. If the test succeeds, there is no such error.
It appears that pytest.approx does not require Numpy to run, but the error message requires Numpy to display the details. Since pytest.approx does not require Numpy to function correctly, it should not require Numpy to display the error.
Output of pip list from the virtual environment:
Package Version
---------- -------
attrs 21.4.0
iniconfig 1.1.1
packaging 21.3
pip 22.0.3
pluggy 1.0.0
py 1.11.0
pyparsing 3.0.7
pytest 7.0.1
setuptools 49.2.1
tomli 2.0.1
pytest and operating system versions:
$ python --version
Python 3.9.0
$ python -m pytest --version
pytest 7.0.1
macOS Big Sur
Version 11.6.2
Minimal example:
import pytest
def test_approx():
assert [1, 2] == pytest.approx([1.001, 2.002])Actual Result:
$ pytest
============================= test session starts ==============================
platform darwin -- Python 3.9.0, pytest-7.0.1, pluggy-1.0.0
rootdir: ****
collected 1 item
test_approx.py F [100%]
=================================== FAILURES ===================================
_________________________________ test_approx __________________________________
def test_approx():
> assert [1, 2] == pytest.approx([1.001, 2.002])
E AssertionError: assert [1, 2] == approx([1.001...02 ± 2.0e-06])
E (pytest_assertion plugin: representation of details failed: /Users/adalessa/Downloads/diffusion-master 2/venv/lib/python3.9/site-packages/_pytest/python_api.py:323: ModuleNotFoundError: No module named 'numpy'.
E Probably an object has a faulty __repr__.)
test_approx.py:5: AssertionError
=========================== short test summary info ============================
FAILED test_approx.py::test_approx - AssertionError: assert [1, 2] == approx(...
============================== 1 failed in 0.04s ===============================
Expected result:
No ModuleNotFoundError: No module named 'numpy'. which makes the whole error message confusing and leads you to believe it failed because Numpy is not installed instead of the fact it was an assertion error.