Function test_catch_unwrapped_exceptions

testing/python/raises_group.py:279–356

()

def test_catch_unwrapped_exceptions() -> None:
    # Catches lone exceptions with strict=False
    # just as except* would
    with RaisesGroup(ValueError, allow_unwrapped=True):
        raise ValueError

    # expecting multiple unwrapped exceptions is not possible
    with pytest.raises(
        ValueError,
        match=r"^You cannot specify multiple exceptions with",
    ):
        RaisesGroup(SyntaxError, ValueError, allow_unwrapped=True)  # type: ignore[call-overload]
    # if users want one of several exception types they need to use a RaisesExc
    # (which the error message suggests)
    with RaisesGroup(
        RaisesExc(check=lambda e: isinstance(e, SyntaxError | ValueError)),
        allow_unwrapped=True,
    ):
        raise ValueError

    # Unwrapped nested `RaisesGroup` is likely a user error, so we raise an error.
    with pytest.raises(ValueError, match="has no effect when expecting"):
        RaisesGroup(RaisesGroup(ValueError), allow_unwrapped=True)  # type: ignore[call-overload]

    # But it *can* be used to check for nesting level +- 1 if they move it to
    # the nested RaisesGroup. Users should probably use `RaisesExc`s instead though.
    with RaisesGroup(RaisesGroup(ValueError, allow_unwrapped=True)):
        raise ExceptionGroup("", [ExceptionGroup("", [ValueError()])])
    with RaisesGroup(RaisesGroup(ValueError, allow_unwrapped=True)):
        raise ExceptionGroup("", [ValueError()])

    # with allow_unwrapped=False (default) it will not be caught
    with (
        fails_raises_group(
            "`ValueError()` is not an exception group, but would match with `allow_unwrapped=True`"
        ),
        RaisesGroup(ValueError),
    ):
        raise ValueError("value error text")

    # allow_unwrapped on its own won't match against nested groups
    with (
        fails_raises_group(
            "Unexpected nested `ExceptionGroup()`, expected `ValueError`\n"
            "  Did you mean to use `flatten_subgroups=True`?",
        ),
        RaisesGroup(ValueError, allow_unwrapped=True),
    ):
        raise ExceptionGroup("foo", [ExceptionGroup("bar", [ValueError()])])

    # you need both allow_unwrapped and flatten_subgroups to fully emulate except*
    with RaisesGroup(ValueError, allow_unwrapped=True, flatten_subgroups=True):
        raise ExceptionGroup("", [ExceptionGroup("", [ValueError()])])

    # code coverage
    with (
        fails_raises_group(
            "Raised exception (group) did not match: `TypeError()` is not an instance of `ValueError`",