'Attempting to set the PDOP value to value inconsisted with HDOP and
VDOP when checking the invariant raises C{ValueError}.'

def test_setDOPWithInvariant(self):

    pe = base.PositionError(hdop=1.0, vdop=1.0, testInvariant=True)
    pdop = pe.pdop
    def setPDOP(pe):
        pe.pdop = 100.0
    self.assertRaises(ValueError, setPDOP, pe)
    self.assertEqual(pe.pdop, pdop)
