To speak to your point Harley, I wonder what would be the point of God creating a universe of puppets? I tend to believe that the overall arch of the "story" is guided to God's purposes. For example: an apostle would betray Jesus. Perhaps it wasn't pre-determined to be Judas, but something about Judas made him the most succeptible to give in to that temptation?
I hesitate to go so far as to say we can "surprise" God, or thwart his will. But unless we can choose and act with some independence, I don't understand why God would spend all this time and energy with us.
And that is EXACTLY the point. We DO choose to act with independence. We just consistently choose NOT to do the things that God would want us to do. And to do anything that God doesn't want is sinful. All God did was to show us this characteristic.
We would act like "puppets" if God created us to purposely fall. What more, God would purposely know that billions of people would be cast into hellfire just because of a test that He devised. This isn't correct theology.
The tree wasn't a "test" because God does not tempt us beyond what we are able. Rather the tree was placed there by God so that it would reveal to us what we were really like. Like Enoch, we would sell our birthright for a meal. Like Adam, he sold Paradise for some fruit. God designed us and ordain that we understand our nature of wandering-our desire to be independent from God. By this we can also understand His grace so that we may come back to the shadow of His wing and be dependent on Him.