'run_main should handle YapfError and sys.exit(1).'

def testShouldHandleYapfError(self):

    expected_message = 'yapf:    Input    filenames    did    not    match    any    python    files\n'
    sys.argv = ['yapf', 'foo.c']
    with captured_output() as (out, err):
        with self.assertRaises(SystemExit):
            yapf.run_main()
        self.assertEqual(out.getvalue(), '')
        self.assertEqual(err.getvalue(), expected_message)
