Add test case to Hamming that shows the difference between len() and chars().count()

[IanWhitney]

I see this solution a lot

let x = "Hi";
let y = "Yo";

if x.len() == y.len() {
//do something
} else {
//do something else
}

But that's tricky in Rust because all strings are UTF-8 and the number of characters != the length of the string slice.

An example: https://play.rust-lang.org/?gist=b0fb8157fd7903333d9441164e0fffaf&version=stable&backtrace=0

I just saw this pop up in Hamming, so maybe exposing this difference via a test in that problem is a good idea.

[kytrinyx]

In the case of hamming for DNA mutations the UTF-8 issue doesn't really come into play. Do we have any other exercises where we could expose this?

[IanWhitney]

In our current problem set? Not really. Anagrams can do it, but that's going to move much later in the sequence. Maybe in a problem we haven't implemented yet?

[kytrinyx]

Yeah, maybe, though there's nothing obvious in the list: http://exercism.io/languages/rust/contribute

Maybe we need a new exercise that focuses on this explicitly. Go has the same thing.

[petertseng]

Since #175 now deals with the difference between bytes and characters, I think the original intent behind this is in fact covered, even if the test was added to a different exercise than Hamming. What say you?

[IanWhitney]

Sounds good.