Blogging in Lisp


How do I run elm-test in Elm 0.19?

Submitted by Bill St. Clair on Mon, 17 Sep 2018 00:24:33 GMT

This is a FAQ, so I'm making a blog post to answer it.

elm-test is still in beta for Elm 0.19. To install it:

$ npm install -g elm-test@beta

The tests directory no longer needs an elm-package.json file (nor does it need elm.json).

Your top-level elm.json file needs to include the following:

    "test-dependencies": {
        "elm-explorations/test": "1.0.0 <= v < 2.0.0"

The easiest way to get it there is with elm-test itself. The following will create a tests directory, containing an example test file, Example.elm, and will add test-dependencies to elm.json.

$ elm-test init

That's it. There is not yet support for running elm-test in the browser, nor is there support for testing DOM output.

billstclair/elm-localstorage is configured with a tests directory to test its JSON encoders and decoders: To run the tests:

$ git clone
$ cd elm-localstorage
$ elm-test

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