Lying in fiction?

It seems that fiction can't lie because, well, it's fiction. But suppose you are reading a novel, and it says: "A woman wearing a woolen cloak entered the room." A chapter later, you learn there was no woman, but a wizard created an illusion. Weren't you lied to by the author?

In those cases where the narrator is a character, at most the narrator lied. But what if the narration is by an impersonal omniscient narrator? Certainly, at the least there is temporary deceit about the world of the fiction, and the deceit is created within the context of a literary style where the reader expects truth about the world of the fiction.

But lying requires assertion. Could we say that statements of an impersonal omniscient narrator are assertions about the world of the fiction? That would seem to be going too far.