The infamous fruit

I think I basically understand the story of Adam and Eve.  But after rereading it one question comes to mind.  God told Adam and Eve that they may partake of the fruits of all the trees except for the tree of knowledge of good and evil.  After the serpent convinced them to eat the fruit that was forbidden God then cursed them.  Making them shameful of their nudity and making them work for their food among other things.   So the question I have is this, the plan that we all choose was to come to earth and be tested and learn.  Was the commandment to not eat the fruit of the tree of knowledge of good and evil meant to be broken?  Because if they had not eaten it how would we have been sent to earth to be tested and gain knowledge?