so far

[Uncle M]

I think I would describe it as an intensifier but I'm not really sure.

I reckon that 'so far untested' is an adjectival phrase describing the object.

Have to go now...!

[David L.]

marciobarbalho: It is not an intensifier. It adds something specific, which is then important to the tense of the sentence. 'so far' means 'up to this point in time'.
'exhaustively' would be an intensifier, as in 'has been tested exhaustively'. To use an intensifier with 'untest' would be like saying, "He is very dead."

Dave:
untested
adjective
(of an idea, product, or person) not subjected to examination, experiment, or experience; unproven : "Analyses based on dubious and untested assumptions."

You're right. As such, 'untested' does not fit with either 'computer' or the 'appliances' as I went on to use in my example. Neither is an 'untested' commodity. We know exactly what they will do and what not. With the appliances, it is not their function that is under scrutiny, but their safe functioning. I left the meaning of 'untested' uncommented upon while I concentrated on tense, and the meaning of 'so far' with present, versus present perfect... which so far seems to be getting lost in it all!!!!!!