public void Deg2DotProduct_ReturnsAngle()
{
// prereq
Approx_Works();
// arrange
float angle = 90;
// act
float dot = PMath.DotD(angle);
// assert
Assert.IsTrue(Mathf.Abs(0 - dot) < 0.0000001f, " 0 ~ " + dot);
Assert.IsTrue(PMath.Approx(0, dot), " 0 ~ " + dot);
}