Quaternion as Roll, Pitch And Yaw. about mathnet-spatial HOT 5 OPEN

var roty = Quaternion.Normalize(new Quaternion(0.0f, 0.0f, (float)Math.Sin(rpy.Z / 2.0), (float)Math.Cos(rpy.Z / 2.0))); // yaw is rotation around Z axis
            var rotp = Quaternion.Normalize(new Quaternion(0.0f, (float)Math.Sin(rpy.Y / 2.0), 0.0f, (float)Math.Cos(rpy.Y / 2.0))); // pitch is rotation around Y axis
            var rotr = Quaternion.Normalize(new Quaternion((float)Math.Sin(rpy.X / 2.0), 0.0f, 0.0f, (float)Math.Cos(rpy.X / 2.0))); // roll is rotation around X axis

            //apply in order of roll, pitch, then yaw        
            var first = rotp.RotateRotationQuat(rotr);
            var second = roty.RotateRotationQuat(first);
            return second;

 yield return new object[]
            {
                new Vector3(2.1114570353895603f, -2.585985022981525f, 0.6664081165354347f), // rpy
                new Quaternion(0.3804738214831853f, -0.3695932081905471f, 0.8350484129621588f, -0.14606395734328323f) // expected quat
            };
            yield return new object[]
            {
                new Vector3(1.2221363972810417f, 2.7458063901769885f, -1.1425980259781825f),
                new Quaternion(0.5291170318308547f, 0.6145316070072362f, -0.5602830425963242f, -0.16872754011902086f)
            };
            yield return new object[]
            {
                new Vector3(-1.1211016954494437f, -0.004126944712585345f, 1.9222979397169384f),
                new Quaternion(-0.30297942912094916f, -0.4368753181928898f, 0.6937524685292732f, 0.4858507325228037f)
            };