Added some now

I have made some changes here to the description to improve readability and also added some random tests

Fun kata, i think "proper spacing" should be clarified something like "space between* per word" for clearity. (Actually that was clarified i didn't read it awsome)

I haven't heard from the duck in a while. I hope she's alive.

I will unpublish the kata until it gets random tests.

What to do when "quack" is part of a word?

Punctuation always makes things tricky, because it makes it difficult to define what is a word, and what is a proper spacing. For example, for input "Hello quack world quack!" it is not immediately clear how the final exclamation mark should be handled, because without proper spec, there is many possibilities:

• "quack!" is not a "quack", so it should be preserved,
• "quack" is removed and ! stays as what's left of the word, leaving us with "... world !",
• it's not a part of a word and should be handled separately from words,
• it's not even clear what punctuation marks are.

Is "Hello, quack-quack! world!" a valid input? What should be the answer?

I will add some. This is my first author so wasn't entirely sure what is required

You should clarify whether a sentence can begin with "quack" and whether it's capitalized or not.

No random tests.

Seems fairly straightforward for a 6kyu (solved in C#). Perhaps more like a 7kyu ihmo.

C# method signature still expects a string as return type

I quite enjoyed this kata. For me perhaps a little more difficult than most other 6kyu I have done. Pays to read the instructions carefully as I omitted to include the string length in my calcuations and sat looking and wondering why my solution was incorrect.

Very nice solution

Great solution!