try the sky test for vigneting only.
Don't bother for the CA test tho.
I doubt very much you will see any CA from a 50mm
lens.
In fact there are different types of CA.
The type you correct for in camera for the
lens is really called lateral CA. Think of it as 'across the image' or the CA is spreading across the frame .. lateral.
The other is called Longitudinal CA. Longitudinal is up and down ways .. or more accurately 'into the image'. May fast f/1.4 type
lenses show this.
Another term for it is bokeh fringing. It shows up (usually) as green/magenta appearance in the
DOF.
But the
lens correction will be for the lateral CA only. Bokeh fringing is hard, if not impossible to correct for.
if you have any zoom type
lenses, they're usually better for seeing CA. The cheaper the better(make that worse) they show it up.