I don't think it was really a test, or at least I doubt that Severus was aware that he was testing Harry when he decided not to enter the restaurant. I think Severus is suspicious by nature and self-sabotage has become his go-to defence mechanism by now. He feels safer on his own. Taking the risk of getting into a relationship with anyone, let alone Harry, scares him half to death. Harry though didn't leave and that, right there, was so unusual a reaction that Severus couldn't help feeling curious about it, and maybe a little bit tempted into trusting Harry. Hopefully, they'll manage to navigate each other's hang-ups with enough patience to grow closer and closer together, until neither one of them can tell where one begins and the other one ends. ;)

I'm thrilled to hear that this little drabble managed to brighten up your day, my dear friend. Thanks, as always, for brightening mine with your kind and lovely comment. <3