pip install pytest-disable

import pytest

@pytest.mark.disable(reason='Test is flaky and fails')
def test_foo():
    assert True==False

def test_bar():
    assert True

$ py.test -sv test_foo.py
===================================== test session starts ======================================
platform darwin -- Python 2.7.10 -- py-1.4.30 -- pytest-2.7.10 -- /usr/bin/python
plugins: disable
collected 2 items

test_foo.py::test_foo SKIPPED
test_foo.py::test_bar PASSED

=================================== short test summary info ====================================
SKIP [1] test_foo.py:3: Test is flaky and fails.
============================= 1 passed, 1 skipped in 0.01 seconds ==============================