Debugging spells is just as much a dark art as spell crafting itself. When I was a young apprentice we didn't have as sophisticated tools as you do now; you had to make sure you noted down your intermediate runes correctly and use those symbols to divine some meaning from the ashes of your failed spell. One time I mixed up my notes with the symbols of a different spell and when I sprinkled the ashes on the stack I was stuck speaking in tounges for a week.

These days of course you can summon a lesser demon to freeze your spell and ask it about the state, but the demons can be tricky and it's easy for novices to make a mistake and allow the demon to run amok - makes a real mess of the lab.

Debugging spells isn't like the fancy debuggers in your modern IDE. You gotta compile the spell with debugging symbols and run it through the spell equivalent of gdb direct in the command line.

But most wizards just go with the ol' "add print statements everywhere" method of debugging.

The devil knowing if the wizard doesn't get it right, he might get hes breakfast, wizard soul!

printspell debugging.