test_ok1/doc/example/xfail_demo.py

import pytest
xfail = pytest.mark.xfail

@xfail
def test_hello():
    assert 0

@xfail(run=False)
def test_hello2():
    assert 0

@xfail("hasattr(os, 'sep')")
def test_hello3():
    assert 0

@xfail(reason="bug 110")
def test_hello4():
    assert 0

def test_hello5():
    pytest.xfail("reason")