And what wouldn't be covered thereon, are most likely homework-type questions, which are typically frowned-upon in the "give me teh codez" format.
In the first case you know it works, and in the second case you know it doesn't work. In neither case does the question "Is my code right" make sense. If you have code that runs without error, but you are uncertain if the output will always be correct, then you want a question and answer site for testing, and naming it to reflect this will cut down on people referring you to Code Review or Stack Overflow.
If you really want a site for fixing code that doesn't work, that is unlikely to attract followers since Stack Overflow already covers this.
If you want a site for finding out if you have the correct approach to a problem, you can ask general algorithm questions on Programmers.
If you want a site for asking about testing your code to find out if it is functioning correctly, you may attract more followers if the name is clearer. However, you will still face the obstacle that many new sites have had to face - there is already a tag on Stack Overflow for testing. Many of those tagged questions are more generic questions about testing rather than presenting a piece of code to be tested, but that reflects the general attitude on many Stack Exchange sites of "show me how" rather than "do it for me". Emphasising a difference in approach that encourages posting code to be tested by others may distinguish your site from Stack Overflow.
(reiterating what I said in comments as an answer)
There are many questions that do not fit in CR or SO. If someone posts these questions there they are severely punished via down voting, question closing, and even eventually banning.
Yet these questions still show up -- in fact they dominate the current set of questions coming into Stack Overflow! (at least my home page is full of marginal-at-best questions.)
This is a severe problem. Experienced/hi-rep people are complaining and/or just giving up on SO because it's not worth their time to wade through the horses**t looking for the pony. (or they stay and bitch -- secretly pleased that they can be cool and disparage the lesser folk (but that's a different issue)).
On the other hand there seem to be a lot of people who are eager and willing to answer these questions -- the "bad" SO questions still get answers (until they are closed.) The people who answer "bad" questions get scolded. When a question gets closed they lose the rep they gained -- hence losing the time they may have spent researching and responding to the "bad" question.
SO gets the reputation as being "unfriendly to newbies" on one hand, and "swamped with useless questions" on the other.
Providing a place that would WELCOME gimme-teh-codz questions, would give those that want to ask and answer these questions a place to play. That's nice, but the real benefit would be the improvement in SO. Think of all the questions to which you could respond. "This question belongs on the Programmers' Help Desk. Go ask it there!"
Yes, there will be lots of "bad" questions on the Programmers' Help Desk, but you won't have to read them!
It certainly seems like "A Good Thing[TM]" to me.