[DataRow(45.0, 315.0, 315.0, 45.0, -90.0, 90.0)]   // both either side of zero

        public void TestGetSlewAngleTo(double s_0, double s_1, double t_0, double t_1, double e_0, double e_1)
        {
            AxisPosition source = new AxisPosition(s_0, s_1);
            AxisPosition target = new AxisPosition(t_0, t_1);

            Angle[] expected = new Angle[] { new Angle(e_0), new Angle(e_1) };
            Angle[] result   = source.GetSlewAnglesTo(target);
            Assert.IsTrue(expected[0] == result[0] && expected[1] == result[1]);
        }