Pytest: str(err) on pytest.raises does not yield the exception message any more

[mwouts]

Thanks for working on this beautiful project!

I use pytest extensively to test a project of mine, and I find that pytest-5.0.0, in combination with Python 3.8.0b1+, does not give the exception message any more if I apply str(err) to an exception err captured with pytest.raises.

A few days ago I was using pytest-4.6.3 with the same version of Python 3.8 dev and had no such issue.

A code like this one should be enough to reproduce the issue:

def test_error_str():
    with pytest.raises(Exception) as err:
        raise Exception("message")

    assert "message" in str(err)

The full details of what happens in the context of my project are available at https://github.com/mwouts/jupytext/issues/269.

[asottile]

you want str(err.value)

this was intentionally changed in 5.0.0, see the changelog: https://pytest.readthedocs.io/en/latest/changelog.html#removals

https://github.com/pytest-dev/pytest/issues/5412

[nicoddemus]

Indeed!

It seems your question has been resolved so I'm closing this for now. Feel free to followup with further questions.

[mwouts]

Sure! I will update my tests to fix this. And many thanks for the quick response!

[asottile]

btw, the reason you only hit this in python3.8 is it appears you're not actually installing pytest and just relying on travis's preinstalled version