I don't understand the purpose of the question. I believe you want String here, it's much more intuitive than [Char]. Idiomatic or not...

[Char], because String is defined as [Char] at basis.

OK, I just wanted to be certain. It's not a trivial change to capture the data from the tests in a more detailed manner, but we'll look into the best way to handle this.

If you don't mind, can you clarify something for me: Are you having trouble with the testing messages, or with error output (for example, syntax errors).

If you are having trouble with the messages coming from the tests, it would be helpful to mention the issue on the discussion board for that specific kata. The kata creator has the ability to wrap results in <pre> tags, which can be helpful when working with strings.

If the issue is coming from the syntax, that's definitely something I think we need to fix.

We probably could improve the testing support across the board to better show complex data. When I get around to working on rebuilding the kata trainer, I'll probably look into providing nicer output of complex data!

I believe it's a bug in the VIM mode editor where it's inserted tabs rather than spaces. I think that's what's causing the discrepency, although I'm not sure why it would render differently (but rendering tabs in a browser is always iffy, because there's poor support for controlling tab width).

It's been added to the issues list. Thanks for reporting it!