I need thorough tests on different voltage biasing of an analog design. I figure all I just need to generate all combination of
1.) conditions (mostly voltage levels, some frequency) and
2.) port connections.

I found that (1) sweeping through all the combination of conditions/parameter is rather easy. What I find challenging is doing all the combination of port connections (2).

This is simply for testing, so I thought there's bound to be a bunch of tools for doing all this combinatorial testing. Components that do not have any real electrical characteristics, but simply "map" each port to another, or in short, "shorts" them -- very combinatorial and functional.

Yet I found none of these. All muxes (so far) that I've seen are modelled after real life products. I've tried looking at Mixed-mode simulators but they too leave electrical characteristics as they are usually defined in S-parameter. With S-parameter analysis I don't have problems with not having perfect infinite impedances, etc, but it's annoying that it's so dependent to frequency.

So can anybody point to the closest implementation of an "ideal" multiplexer?

 

Can one define such an ideal component, just maps ports in SPICE?

 

So many kinds of Spice, which spice do you used?
CD4051?
Try 4051.asy and 4051b.asy for LTSpice
Or you want to try CD4066B for LTSpice in the directory C:/Program Files/.../lib/sym/Digital/CD4000/CD4066B.asy

 

Certainly you can use an ideal "switch" model which most version of Spice have, I believe.
You can select the ON and OFF resistance values to be any arbitrary value you like.