public void AxisFromStringTest()
{
Assert.AreEqual(Axis.x, Axes.AxisFromString("x"));
Assert.AreEqual(Axis.y, Axes.AxisFromString("y"));
Assert.AreEqual(Axis.z, Axes.AxisFromString("z"));
Assert.ThrowsException <ArgumentException>(()
=> Axes.AxisFromString("Exc"));
Assert.ThrowsException <ArgumentNullException>(()
=> Axes.AxisFromString(null));
}