Option for pytest.fail to not print exception context

[VincentVanlaer]

Context

Currently, one of the ways to use pytest.fail is to include all of the necessary information in the reason field and disabling the traceback with pytrace = False. While this does suppress tracebacks of the exception itself and any exceptions in the context, it still prints the context. I use this in python-trio/pytest-trio#136 for example to report full tracebacks when a timeout happens (capturing all async tasks). Currently, this implementation prints the set of tracebacks twice as an internal exception (which also contains the tracebacks) is converted to a test failure with pytest.fail.

Feature request

I would like to have a way to suppress this context as well, either by default if pytrace = False is set, or with another option. This is the behavior I would have expected from pytrace in the first place.

Alternatives

It is possible to do some juggling with the exceptions to remove the context as follows:

import pytest


def test_fail():
    try:
        import some_missing_package
    except ImportError:
        try:
            pytest.fail(reason="You need to install some_missing_package for this test to succeed", pytrace=False)
        except BaseException as e:
            e.__cause__ = None
            raise

I think this would be reasonable to implement in a plugin for example, but might be a bit to cumbersome/obscure for use in tests. But that is not where my use case lies, so this might a case of the XY problem. Another solution would be to use a report hook to customize the reporting of certain special exceptions.

It might be that these alternatives are acceptable (I presume that this case is not a common occurrence) and adding this feature is not worth the maintenance/testing/change in behavior. But I believe it is still worth considering at least.