Dear Highdose, you are right: that particular account of Abraham contains some contradictions.
First of all, what you said: according to many scriptures, like 1 Samuel 16:7, "... as for Jehovah, he sees what the heart is", so all Jehovah needed to do was read his heart and imagine how Abraham would react. So isn't it weird that at Genesis 22:12, immediately after the test, Jehovah says: "... for NOW I do know that you are God-fearing in that you have not withheld your son..."?, implying the test had to actually be carried out for God to know what Abraham's reaction would be?
Secondly, putting somebody's faith to the test goes contrary to James 1:13: "...For with evil things..." (you all know the rest by heart).
And, last but not least, what kind of a psychopath must one be to put one's own son through this terrible ordeal: "Kill your beloved little child to prove how much you love me"?
I have a far higher opinion of God, if He exists, than to believe such a deplorable account actually took place.