I agree with @ewhoambra, the solution will fail when implementing it for "Hello I am Joe".

This doesn't work if there are multiple spaces between words in the phrase

For example, the string "most   trees are  blue" should be changed to "Most   Trees Are  Blue" but with this code it causes a System.IndexOutOfRangeException error.

This does not work if the input is "jack aNd jill". it does not convert the N to a lower case letter.

A pythonian answer.

Sure, no problem. Made the generator readable. Let me know if you'd rather I removed it altogether.

I'd approve this if it either removed the random test cases or made the code generating them more readable.

LazyWolf's translation is a bit better than yours at this point. I'd also prefer not cloning the null cases of the Java translation.