The idea of the Bechdel test originated in a 1985 cartoon by Alison Bechdel.
In it, a character describes the test as something she uses to determine which movies she'll see. If a movie fails the test, she doesn't see it. She notes that the last movie she could actually see was 1979's Alien.
However, I'm not sure that Alien actually qualifies.
As I recall, there are two female characters: Ripley and Lambert. I don't remember them actually having a significant conversation in the film. The best I can remember is Ripley trying to get Lambert to pull it together after Captain Dallas is killed, and that's arguably a conversation about a man.
Does Alien actually pass the Bechdel test?