IPython/utils/tests/test_shimmodule.py

import sys
import warnings

import nose.tools as nt

from IPython.utils.capture import capture_output
from IPython.utils.shimmodule import ShimWarning

def test_shim_warning():
    sys.modules.pop('IPython.config', None)
    with warnings.catch_warnings(record=True) as w:
        warnings.simplefilter("always")
        import IPython.config
    assert len(w) == 1
    assert issubclass(w[-1].category, ShimWarning)