elm-spec

End-to-end testing for your Elm apps and components.

Features

• Can test apps or separate components
• Task based steps and assertions (allows createing custom ones easily)
• Create composite steps from other steps
• DOM steps and assertions (click, containsText, valueEquals, etc...)
• Mock HTTP requests and report not mocked requests
• before / after hooks
• Run tests in the console (via jsdom)
• Run tests with elm-reactor with HTML Report
• Run files one at a time elm-spec spec/SomeSpec.elm
• Run tests one at a time elm-spec spec/SomeSpec.elm:2

CLI

You can install the CLI with either of the following commands:

npm install elm-spec -g or yarn global add elm-spec

elm-spec [glob pattern or file:testID] -f format

Options:
  --format, -f  Reporting format
               [choices: "documentation", "progress"] [default: "documentation"]
  --help        Show help                                              [boolean]

Adding the package

Add gdotdesign/elm-spec as a dependency to your elm-package.json.

  "dependencies": {
    "gdotdesign/elm-spec": "1.0.0 <= v 2.0.0"
  }

And then install with elm-github-install using the elm-install command.

Quick Start

Here is an exmaple of testing a simple component:

import Spec exposing (..)
 
import Html.Events exposing (onClick)
import Html exposing (div, text)
 
type alias Model
  = String
 
type Msg
  = Set
 
init : () -> Model
init _ =
  "Empty"
 
update : Msg -> Model -> ( Model, Cmd Msg )
update msg model =
  case msg of
    Set ->
      ( "Something", Cmd.none )
 
view : Model -> Html.Html Msg
view model =
  div [ onClick Set ] [ text model ]
 
specs : Node
specs =
  describe "Example"
    [ it "clicking on the div should change the text"
      [ assert.containsText { text = "Empty", selector = "div" }
      , steps.click "div"
      , assert.containsText { text = "Something", selector = "div" }
      ]
    ]
 
main =
  runWithProgram
    { subscriptions = \_ -> Sub.none
    , update = update
    , view = view
    , init = init
    } specs

And open the file in elm-reactor or run it wit the elm-spec command:

$ elm-spec spec/ExampleSpec.elm
◎ spec/ExampleSpec.elm
  Example
    ✔ clicking on the div should change the text
      Element div contains text "Empty"
      Clicked: div
      Element div contains text "Something"

1 files 1 tests:
 3 steps: 3 successfull, 0 failed, 0 errored
 0 requests: 0 called, 0 not called, 0 unhandled

Defining tests

You can define tests with the it or test functions:

it "does something"
  [ step1
  , assertion1
  , step2
  , assertion2
  ]

Each test can have an unlimited number of steps (Task Never Outcome) which are executed in sequence.

Before every test the given application is reset and a fresh DOM is created.

Defining Groups

You can define groups that can have an tests, hooks and groups. There are three functions that do the same thing: group, context, describe.

context "Something"
  [ describe "Something else"
    [ it "does something"
      [ step1
      , assertion1
      ]
    ]
  ]

Hooks

Elm-spec allows you to append and prepend steps and assertions before each test with the before and after functions.

These functions can be defined in a group and it will add it's steps to each test in that group and it's descendant groups tests (recursively).

context "Something"
  [ describe "Something else"
    [ before
      [ preparationStep1
      ]
    , after
      [ cleanupStep1
      ]
    , it "does something"
      [ step1
      , assertion1
      ]
    ]
  ]

Steps and Assertions

The following steps are available in the steps record:

{ dispatchEvent : String -> Json.Value -> String -> Step
, getAttribute : String -> String -> Task Never String
, setValue : String -> String -> Step
, getTitle : Task Never String
, clearValue : String -> Step
, getUrl : Task Never String
, click : String -> Step
}

And the following assertions are available in the assert and assert.not records:

{ attributeContains : AttributeData -> Assertion
, attributeEquals : AttributeData -> Assertion
, inlineStyleEquals : StyleData -> Assertion
, valueContains : TextData -> Assertion
, classPresent : ClassData -> Assertion
, containsText : TextData -> Assertion
, styleEquals : StyleData -> Assertion
, elementPresent : String -> Assertion
, elementVisible : String -> Assertion
, titleContains : String -> Assertion
, valueEquals : TextData -> Assertion
, titleEquals : String -> Assertion
, urlContains : String -> Assertion
, urlEquals : String -> Assertion
}

Step groups

You can define a new step that is composed of many other steps but appear as one step in the results with the stepGroup function. If any of the defined steps fails the new step fails as well.

myStep =
  stepGroup "Descripiton of the step"
    [ step1
    , assertion1
    ]
 
spec =
  it "does something"
    [ myStep
    , step2
    ]

Examples

You can see examples of tests written in elm-spec in here:

• https://github.com/gdotdesign/elm-ui/tree/master/spec
• https://github.com/gdotdesign/elm-dom/tree/master/spec
• https://github.com/gdotdesign/elm-storage/tree/master/spec