'Tests the DOP values in a position error, and the repr of that
position error.
@param pe: The position error under test.
@type pe: C{PositionError}
@param pdop: The expected position dilution of precision.
@type pdop: C{float} or L{None}
@param hdop: The expected horizontal dilution of precision.
@type hdop: C{float} or L{None}
@param vdop: The expected vertical dilution of precision.
@type vdop: C{float} or L{None}'

def _testDOP(self, pe, pdop, hdop, vdop):

    self.assertEqual(pe.pdop, pdop)
    self.assertEqual(pe.hdop, hdop)
    self.assertEqual(pe.vdop, vdop)
    self.assertEqual(repr(pe), (self.REPR_TEMPLATE % (pdop, hdop, vdop)))
