0475b1c925
Test:
`warnings.warn()` expects that its first argument is a `str` or a
`Warning`, but since 9454fc38d3
`pytest.warns()` no longer allows `Warning` instances unless the first
argument the `Warning` was initialized with is a `str`. Furthermore, if
the `Warning` was created without arguments then `pytest.warns()` raises
an unexpected `IndexError`. The new tests reveal the problem.
Fix:
`pytest.warns()` now allows using `warnings.warn()` with a `Warning`
instance, as is required by Python, with one exception. If the warning
used is a `UserWarning` that was created by passing it arguments and the
first argument was not a `str` then `pytest.raises()` still considers
that an error. This is because if an invalid type was used in
`warnings.warn()` then Python creates a `UserWarning` anyways and it
becomes impossible for `pytest` to figure out if that was done
automatically or not.
[ran: rebased on previous commit]
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508 B
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4 lines
508 B
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:func:`pytest.warns` now validates that :func:`warnings.warn` was called with a `str` or a `Warning`.
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Currently in Python it is possible to use other types, however this causes an exception when :func:`warnings.filterwarnings` is used to filter those warnings (see `CPython #103577 <https://github.com/python/cpython/issues/103577>`__ for a discussion).
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While this can be considered a bug in CPython, we decided to put guards in pytest as the error message produced without this check in place is confusing.
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