Why does an omniscient God test people?

My answer to a question from a friend:

What’s your thoughts on why an omniscient God gives people tests throughout the whole Bible already knowing what they’ll do?

i) Although he knows what they will do, they don't know what they will do, and the very test may influence what they will do. There's a sense in which the exercise can make a contribution to its own outcome. Having to actually through the ordeal or experience may change the individual in the process. He ends up in a different place than where he started. The challenge is transformative. 

ii) In addition, there's a reason these events are recorded. They are not primarily for the benefit of the test-subject but the reader. It's a way for readers to learn about God's M.O. The reader is learning about God's character through the experience of the Patriarchs (among others). 

iii) People like Abraham had a pagan background. So they didn't know if Yahweh was trustworthy. They had to learn from experience what kind of God Yahweh was. Is he like the fickle, malicious gods of the pagan pantheon, or is he different?