This is the procedure that Starlight Xpress uses. Similar to what Joshua mentioned in the 2nd post.
However this test is for the camera only, not the image train (filter wheel, OAG, focuser etc).
Our method involves reflecting laser light from the CCD surface and observing how the reflections rotate on a screen
when the camera is revolved. The CCD is properly aligned when the bright reflection from the CCD cover slip is
stationary on the screen, despite rotating the camera through 360 degrees.
https://www.sxccd.com/maintenance_info/Aligning_CCD.pdf