I think that Abraham was really expecting God to provide a sacrifice.
This is because 22:8 And Abraham said, My son, God will provide himself a lamb for a burnt offering. I think that Abraham knew in a way he was being tested and that he believed that in the end God would send a sacrifice of a lamb or even bring Isaac back if need be. For Abraham he truly put his faith in God. Then God sent an angel 22:12 And he said, Lay not thine hand upon the lad, neither do thou any thing unto him: for now I know that thou fearest God. And Abraham faith paided off 22:13 And Abraham lifted up his eyes, and looked, and behold behind him a ram caught in a thicket by his horns: and Abraham went and took he ram, and offered him up for a burnt offering in the stead of his son.
I have to agreen with blessed me with answer to Did you ever receive a last-minute provision from God?.