Good point. This solutions does not correctly handle upper camel case.

The test_solution_randomly function strips the uppercase letter from the start of the sentence with:

            sentence.push_str(&word_selection.next().unwrap()[1..]);

So I take it this problem is only intended for lower camel case.

The problem statement should probably be made to be more specific.

I see someone already reported the issue:

https://www.codewars.com/kata/5208f99aee097e6552000148/discuss/rust#6181ac3bac59440057e75f57

Doesn't this function fail to account for a string that may start with a capital letter?

Take the example "CamelCase", this function output " Camel Case" instead of the intended "Camel Case".