The issue of whether mankind can keep integrity to God is a huge strawman that the Watchtower Society loves to invoke. It claims that the issue had to be proved to angels by actually allowing Satan to test mankind in various ways, and that a good way of doing this was to allow Satan to test Job. That this is a ridiculous claim can be shown in several ways:
(1) If God fully knows how humans are built and all of man's parts "are down in writing", then mankind's ability to keep integrity is part of the "design specification". Since the Bible states that some angels in Noah's day sinned by creating fully human bodies for themselves, it follows that these angels fully know the "design spec". Therefore, if any such supernatural beings raised a question about mankind's abilities, God would simply have to tell them, "Read the design spec", and the issue would be settled. In particular, a claim that no man can keep integrity to God would be easy to verify. So would a claim that a specific man could not keep integrity.
[Humans are created with emotions and so are spirit entities. How can you be design specific on something that is random? In otherwords, you might like meat when another does not. This is how a person becomes a person, by their personality traits. You will react to one occurrance in disgust, while another applauds it. This is learning good and evil]
(2) Mankind is comprised of a large number of individuals with all manner of proclivities. Some are going to do bad things no matter what. Some are going to do good things no matter what. Some will go either way depending on any number of factors. Therefore, testing a single man -- Job -- gives information only about Job, not about anyone else.
[Job is an account in example. Not everything that occurred in the life of Jesus Christ was written. Did the bible tell you how many times he sat down to eat? Great examples are given as a learning tool. Jobs example applys to all that have suffered, and how they will be rewarded many times over.]
(3) The notion of testing at the hands of Satan is unfair. Satan is said to be a supernatural being with power to control natural forces, and intelligense far beyond what humans possess. To allow such a being to test any human is obviously unfair. To allow such a being to kill dozens of innocent people in an attempt to win a bet with God is extremely unfair on the part of God. Are humans mere pawns in a cosmic chess game? Were Job's children and others completely expendable and mere objects of sport? Does it make sense that Job would be ok with God allowing his children to be killed in this sport and then 'replaced' with other children, as if children were replaceable possessions? Of course not. That's why the Job myth is obviously the product of an ancient patriarchal culture in which wives and children were mere property. In such a culture it makes a certain amount of sense.
[You are correct, it is unfair for satan to use his strength against mankind, however satan had to be given free will also. Jehovah wants no offspring to parish, not even satan. Satan was one of first in creation and has great wisdom. Jah had to turn His back to allow those in the heavens to reign freely also. The war in the heavens is in retribution to all that satan and his followers have done to those upon the earth. Jehovah suffers also, so He knows our pain. It will come to an end and we will all flourish throughout the universe. Consider 6000 years or so to be a minimal amount of suffering in comparison to everlasting life. This is why JAH is the Almighty God, because He is aware of what His creation needs in order to learn great wisdom.]
AlanF