See, for example, here: https://groups.google.com/forum/#!topic/elm-discuss/qhLsLThplUo
An approach in which one waits "longer" to convert requests to commands appears to be more readily testable. (That said, I haven't taken to writing unit tests yet for this code and while one can compare for equality, command like entities will tend to involve tagger functions which may result in fatal runtime errors in those equality checks.) Mark On Monday, November 7, 2016, Oliver Searle-Barnes <oli...@opsb.co.uk> wrote: > This is an area I've been a little uncomfortable with. There seems two be > a couple of options though: > > 1) https://github.com/avh4/elm-testable - I haven't used it but it seems > that it provides replacement commands that you can run assertions against. > This approach seems limited as it only solves the problem for a predefined > set of commands. > > 2) Another approach, which I also haven't tried yet: Instead of returning > commands from your update, model the effects yourself and only convert them > into commands at the last minute when returning them from your main/update. > For instance you might return MyEffects.request(endpoint, verb, payload, > GoodResponse, BadResponse). This would allow you to just use assertEquals > on the effects returned from your update. Something that would need to be > taken care of though is a replacement for Cmd.map. > > > > > On Monday, 7 November 2016 09:54:53 UTC+1, Simon wrote: >> >> ... which is ironic given all emphasis on 'effects as data'.... >> >> On Monday, 7 November 2016 09:51:56 UTC+1, Austin Bingham wrote: >>> >>> I asked more or less the same question about a month ago and got no >>> responses: >>> >>> https://www.reddit.com/r/elm/comments/593vua/how_to_test_ >>> the_complete_update_cycle/ >>> https://groups.google.com/d/msg/elm-discuss/634UXiZjRFQ/lVeDED1oBQAJ >>> >>> The only practical answer right now seems to be to use elm-testable, >>> though I haven't actually tried it myself. >>> >>> This feels like a real blind-spot in the elm ecosystem. The generation >>> and handling of Cmds is central to a properly functioning app, but there >>> doesn't seem to be any first-class way to test e.g. Update without driving >>> the entire app from the top-level. >>> >>> On Mon, Nov 7, 2016 at 8:28 AM Simon <hotb...@gmail.com> wrote: >>> >>>> I've often worried about the commands bit. >>>> For the view side, you need to test that you are deriving the right >>>> data to render, while it is Evan that needs to test that, given certain >>>> data, expected DOM elements get produced? >>>> >>>> >>>> On Monday, 7 November 2016 07:44:36 UTC+1, Francesco Orsenigo wrote: >>>>> >>>>> How do you write unit tests to ensure that an `update : Msg -> Model >>>>> -> ( Model, Cmd Msg )` function is producing the correct commands? >>>>> What if the function is supposed to produce several commands batched >>>>> together? >>>>> >>>>> Same thing for a `view : Model -> Html Msg`. >>>>> Suppose I want to test whether, given a particular model, it will >>>>> display the correct number of list items. >>>>> Do people write tests for this? >>>>> Right now the only way to write this kind of tests I can think of is >>>>> creating the whole html tree as I expect it to be rendered, and comparing >>>>> it via == with the function output. >>>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "Elm Discuss" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to elm-discuss...@googlegroups.com. >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> -- > You received this message because you are subscribed to the Google Groups > "Elm Discuss" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to elm-discuss+unsubscr...@googlegroups.com > <javascript:_e(%7B%7D,'cvml','elm-discuss%2bunsubscr...@googlegroups.com');> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Elm Discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to elm-discuss+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
