Who is assuming that? The comments let you write your code quickly, and then of course you test to make sure it works. Comments do not obviate the need for testing, they just mean you don't have to (if up to date) read tons of source code.
Who are you writing the comments for? If yourself as pseudocode, fine, but get rid of them when you are finished. If you are writing them for another developer down the road, that developer will either ignore them because he really doesn't know for sure the comments can be trusted, or will blindly trust the comments and now and then will get burned.