IINM, Ha-Satan is simply God's Advocate. He was testing Yeshua bin Yosef the same as he had test Job. It was his duty as a member of God's angels. The whole Lightbringer/Devil is a fabrication and/or morphing of damn near every religion's belief in an Advocate for Humanity who does so against the wishes of the gods. The Lightbringer (the Serpent in The Garden), as opposed to Ha-Satan, did what he did for Mankind to help us 'evolve' and take our place along with the others outside The Garden (the inhabitants of The Land of Nod that Caine lives among after being cast out comes to mind).
So, in conclusion, Ha-Satan is not a 'bad guy' anymore than The Lightbringer is a 'bad guy'. That is if you take Christian mythology (as opposed to Christian teaching) at face value.
John 8:44
Ye are of your father the devil, and the lusts of your father ye will do.
He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own: for he is a liar, and the father of it. 45 And because I tell you the truth, ye believe me not. 46 Which of you convinceth me of sin? And if I say the truth, why do ye not believe me? 47 He that is of God heareth God's words: ye therefore hear them not, because ye are not of God.
Rev 12
7 And there was war in heaven: Michael and his angels fought against the dragon; and the dragon fought and his angels, 8 And prevailed not; neither was their place found any more in heaven. 9 And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.
10 And I heard a loud voice saying in heaven, Now is come salvation, and strength, and the kingdom of our God, and the power of his Christ: for the accuser of our brethren is cast down, which accused them before our God day and night. 11 And they overcame him by the blood of the Lamb, and by the word of their testimony; and they loved not their lives unto the death. 12 Therefore rejoice, ye heavens, and ye that dwell in them. Woe to the inhabiters of the earth and of the sea! for the devil is come down unto you, having great wrath, because he knoweth that he hath but a short time.