>Even (You) have never faced such a test...
What did he mean by this?
Can we start using better resolution images for Snoke
Kylo has to confront his father and finally make a permanent choice of allegiance to either side of the force. It's meant to mirror the Obi-Wan/Vader fight from ANH visually, but thematically it's the same thing Luke went through when he confronted Vader in Empire.
Snoke knows seeing Han will bring up old memories and it's stated in dialogue that Kylo is struggling to keep the light side at bay. It is literally the most difficult task he's faced thus far as the person he's become - or that he's trying to become.
He's in the same position for the entire movie anyway