Afaict on a quick skim, the elm guide makes no reference to testing, and other than fully specifying your dependencies with only pure functions, doesn’t seem to resolve the question of minimal state to generalize a test.
Html might be inherently simpler because the total output state is simpler (just the html), but then you have things like caching, cookies, browser versions, etc, which elm does not appear to capture in its dependencies
Elm has a time travelling debugger and the ability to dump all the state transitions and replay them elsewhere, for example to reproduce a bug. Seems relevant to me.
