Here's a good litmus test for friendship: If I were a Hogwarts student and I had two supposed best friends, here's a way I might know which one was my true best friend: If the Triwizard Tournament were held and I didn't enter but my name came out of the Goblet of Fire anyway, I would pay close attention to how my supposed best friends reacted. If I told best friend 1 the truth that I hadn't put my own name in the Goblet of Fire and he mistrusted me and abandoned me and I told best friend 2 the same truth that I hadn't put my own name in the Goblet of Fire and she immediately believed me without question, I would know that best friend 1 was a disloyal fair weather friend and would permanently end my friendship with him. I would also know that best friend 2 was my loyal ride or die Bestie and would further embrace my friendship with her.