Input size (matrix size and entries size) should be mentioned, because int is too small to store diagonal products in general. Overflow doesn't happen in the tests, but this is a big concern in general.

I would rather use int[,] instead of jagged arrays while dealing with matrixes...

Really enjoyable kata! Love it.

language: C#

• if you need more info, just let me know

Mention the language when having a problem and the kata has more than one available, please.

2nd round of tests contains erros - there are 3 params in the function instead of 2...

Marking as resolved.

fixed, thanks!

Random tests added. Thanks!

changed, thank you!

Sample tests fail to compile.

Test Results:
  Log
    tests/Fixture.cs(25,5): error CS1513: } expected

Matrices are rectangular, so int[,] should be a better type for them.

It helped! Now Iam back on the track, thanks guys!

Unfortunately, documentation and materials to support authors are not completely ready yet, but there's some pages which could possibly help you. If you want to create a kata and ensure its good quality, you can read following information:

• Documentation on Content Authoring, which is still work in progress, but quality guidelines are more or less stable and conforming to them should help a kata a lot,
• Creating a kata tutorial, which is not published yet and still in progress, but might be useful. I personally don't like it though,
• Recently published tutorial for creating a kata in JS, C or Python (with other languages slowly incoming). There's no article for C# (yet), so you'd have to get grasp of NUnit by yourself, but ideas are pretty similar across languages. You can think of [TestFixture] as equivalent of describe, and [Test] or similar as equivalent of it.

I know that all of this is not much of a help, but I think it can give at least some hints or ideas.