Your right. You can have deceptive tests. i.e. Israel at its closest is a 650 mile shot. The missile they have can easily go 750 miles. So you position the missile 700 miles from Israel program it for a 700 mile shot to see how close you would be to hitting Israel.
Then announce you are going to try to get 1200 miles out of the missile. You can do that 1200 miles inside Iran from the NW corner to the SE corner of the country. So you shoot it and it comes down 700 miles away where you wanted it to hit, and announce it is a failure because it didn't make the 1200 miles. - tom
Iran already has mobile missile launchers reportedly moving on a daily basis in the southwest of the country. From there they can deliver their payload to Israel.