Class RaisesExc

src/_pytest/raises.py:532–720

.. versionadded:: 8.4 This is the class constructed when calling :func:`pytest.raises`, but may be used directly as a helper class with :class:`RaisesGroup` when you want to specify requirements on sub-exceptions. You don't need this if you only want to specify the type, sinc

@final
class RaisesExc(AbstractRaises[BaseExcT_co_default]):
    """
    .. versionadded:: 8.4


    This is the class constructed when calling :func:`pytest.raises`, but may be used
    directly as a helper class with :class:`RaisesGroup` when you want to specify
    requirements on sub-exceptions.

    You don't need this if you only want to specify the type, since :class:`RaisesGroup`
    accepts ``type[BaseException]``.

    :param type[BaseException] | tuple[type[BaseException]] | None expected_exception:
        The expected type, or one of several possible types.
        May be ``None`` in order to only make use of ``match`` and/or ``check``

        The type is checked with :func:`isinstance`, and does not need to be an exact match.
        If that is wanted you can use the ``check`` parameter.

    :kwparam str | Pattern[str] match:
        A regex to match.

    :kwparam Callable[[BaseException], bool] check:
        If specified, a callable that will be called with the exception as a parameter
        after checking the type and the match regex if specified.
        If it returns ``True`` it will be considered a match, if not it will
        be considered a failed match.

    :meth:`RaisesExc.matches` can also be used standalone to check individual exceptions.

    Examples::

        with RaisesGroup(RaisesExc(ValueError, match="string"))
            ...
        with RaisesGroup(RaisesExc(check=lambda x: x.args == (3, "hello"))):
            ...
        with RaisesGroup(RaisesExc(check=lambda x: type(x) is ValueError)):
            ...
    """

    # Trio bundled hypothesis monkeypatching, we will probably instead assume that
    # hypothesis will handle that in their pytest plugin by the time this is released.
    # Alternatively we could add a version of get_pretty_function_description ourselves
    # https://github.com/HypothesisWorks/hypothesis/blob/8ced2f59f5c7bea3344e35d2d53e1f8f8eb9fcd8/hypothesis-python/src/hypothesis/internal/reflection.py#L439

    # At least one of the three parameters must be passed.
    @overload
    def __init__(
        self,
        expected_exception: (
            type[BaseExcT_co_default] | tuple[type[BaseExcT_co_default], ...]
        ),
        /,
        *,
        match: str | Pattern[str] | None = ...,
        check: Callable[[BaseExcT_co_default], bool] | None = ...,
    ) -> None: ...