elm-doc-test

Verify examples in your docs.

Install

$ npm i elm-test -g
$ npm i elm-doc-test -g
$ elm-test init

Setup

$ touch tests/elm-doc-test.json

elm-doc-test.json contains information on which files contain verified examples and where to find them.

{
  "root": "../src",
  "tests": [
    "Mock",
    "Mock.Foo.Bar.Moo"
  ]
}

It's recommended to add ./tests/Doc to your .gitignore.

Writing Verified Examples

Verified examples look like normal code examples in doc-comments.
Code needs to be indented by 4 spaces. You can specify the expected result of an expression, by adding a comment --> (the > is important) and an expected expression.

{-| returns the sum of two int.

    -- You can write the expected result on the next line,

    add 41 1
    --> 42

    -- or on the same line.

    add 3 3 --> 6

-}
add : Int -> Int -> Int
add =
    (+)

You can write examples on multiple lines.

{-| reverses the list

    rev
        [ 41
        , 1
        ]
    --> [ 1
    --> , 41
    --> ]

    rev [1, 2, 3]
        |> List.map toString
        |> String.join ""
    --> "321"
-}
rev : List a -> List a
rev =
    List.reverse

You can specify imports, if you want to use a module or a special test util.

{-|
    import Dict

    myWeirdFunc (Dict.fromList [(1, "a"), (2, "b")]) [2, 1]
    --> "ba"
-}

Running DocTests

elm-doc-test only converts your doc-tests into elm-tests. You have to use elm-test in order to run them.

$ elm-doc-test && elm-test tests/Doc/Main.elm

By default the first command creates the tests at tests/Doc/. If you want to have them at a custom location use the --output argument (e.g. elm-doc-test --output my/custom/path/ will create the tests at my/custom/path/Doc/).

Also by default the first command looks for the config file at tests/elm-doc-test.json. If you want it to load a specific config file use the --config argument (e.g. elm-doc-test --config my/custom/path/elm-doc-test.json will read the config from my/custom/path/elm-doc-test.json).

Examples

You can run the examples using:

npm start