would needs random tests! (even for a duplicate... ;) )
At least for C#, there aren't actually many similar ones. Searching for "rotate matrix" only yields one comparable result. I certainly wouldn't have noticed this as a duplicate and I solved a lot of C#-kata :)
For Java, method should be called rotate instead of Rotate
Hi and welcome;-), i see it's your first published kata, but it's a duplicate. There are many others like this, so you should search similar or same katas before publishing (look for "rotate matrix")... So you should change something to solve this "issue"... By the way, no random tests...