`pytest.xfail` and `pytest.skip` as context managers

What's the problem this feature will solve?

For some reason we may expect a specific part of the test to fail or to be skipped (maybe conditionally), usually because there's a blocking issue to be resolved.

Describe the solution you'd like

We propose exposing pytest.xfail and pytest.skip (or their equivalents) as context managers, just like pytest.raises. So we may have:

def test_match():
    assert match("hello", "hello")
    with pytest.xfail("external/matcher#123: match doesn't support case-insensitive matching yet"):
        assert match("World", "WORLD")

pytest.skip is used for a similar purpose, only when the broken tests are not even going to be run.

Alternative Solutions

We can, of course, break a single test into multiple and mark them with @pytest.mark.xfail and @pytest.mark.skip. This is less favorable because tests may be organized and can share some setup codes (which may not be exposed by fixture). Most importantly, we may want the test to early fail before it ever touches the with pytest.xfail block, and this is not achievable without the help of plugins like pytest-dependency.

Additional context

We would also like to see strict= argument in the current pytest.xfail.

Start by reading the existing pytest.xfail and pytest.skip APIs and compare their behavior with pytest.raises as a context manager. Clarify how scoped skipping and expected failures should behave, including the requested strict= argument; done means the feature is specified and tested for conditional blocks and early failures.