Im doing a planet/etc simulation for a computational physics class, and I think I have managed to make it include eccentricity correctly, but I have no idea how to test that. The parameters I am passing in are the orbital period, orbital radius, and eccentricity. (Im also working on a version that goes off of only initial position and a velocity vector, but thats a different question)

How can I tell if what I am looking at here *is* correct, or if it just *looks* correct, but in reality is totally wrong?

Pic related, its the graphical output when simulating pluto.


Here is the relevant code (python using vpython for graphics)
https://hastebin.com/qisuleqebu.py