MVC web app development test-driven development has always bothered me. I can easily test my models/controllers but to verify that the app HTML isn't borked I have to rely on strict HTML compilation tools (like HAML) and/or slow/painful frontend integration tests that require button clicking, HTML parsing, and form-element filling.

I've always wanted a higher-level way to author and test HTML and I always come back to a more programmatic/declarative way of generating HTML as the best way. I'm not sure if Elm is the answer but I think it's at least a good discussion starter.