https://github.com/avh4/elm-testable

Makes Cmds and Tasks testable
https://github.com/avh4/elm-testable

deprecated elm testing

Last synced: about 2 months ago
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Makes Cmds and Tasks testable

• Host: GitHub
• URL: https://github.com/avh4/elm-testable
• Owner: avh4
• Created: 2016-04-27T06:20:10.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2021-05-26T20:45:37.000Z (over 3 years ago)
• Last Synced: 2024-04-13T16:20:20.782Z (8 months ago)
• Topics: deprecated, elm, testing
• Language: Elm
• Homepage: http://package.elm-lang.org/packages/avh4/elm-testable/latest
• Size: 330 KB
• Stars: 41
• Watchers: 6
• Forks: 5
• Open Issues: 7
• Metadata Files:
  • Readme: README.md

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README

        
## Deprecated

Now use [avh4/elm-program-test](https://elm-program-test.netlify.app) instead.  (elm-testable only works with ELm 0.17)

## ~~Note:~~

~~elm-testable does not support Elm 0.18.  A new package is currently in development that will allow testing of Cmds, Tasks, and Subs without the need for elm-testable's wrappers.  More details will be posted to elm-discuss when it is available.  (See the [rewrite-native branch](https://github.com/avh4/elm-testable/tree/rewrite-native).)~~

[![Build Status](https://travis-ci.org/avh4/elm-testable.svg?branch=master)](https://travis-ci.org/avh4/elm-testable)

# avh4/elm-testable

This package allows you to write components that follow the Elm Architecture in a way that is testable.

To allow this, elm-testable provides testable versions of the `Task`, `Effects`, and `Http` modules,

as well as `Testable.TestContext` to test testable components and `Testable` to integrate testable components with your Elm app.

## Example testable component

The only difference between a testable component and a standard component is the added `Testable.` in several imports.  (With the exception of `Cmd`, which conflicts with the default import of `Platform.Cmd` in Elm 0.17.)

Here is the diff of converting `RandomGif.elm` into a testable component:

```diff

diff --git b/examples/RandomGif.elm a/examples/RandomGif.elm

@@ -6,8 +6,9 @@ import Html exposing (..)

 import Json.Decode as Json

-import Http

-import Task

+import Testable.Cmd

+import Testable.Http as Http

+import Testable.Task as Task

 

 @ -20,7 +21,7 @@ type alias Model =

-init : String -> String -> ( Model, Cmd Msg )

+init : String -> String -> ( Model, Testable.Cmd.Cmd Msg )

 init apiKey topic =

@@ -36,7 +37,7 @@ type Msg

 

-update : Msg -> Model -> ( Model, Cmd Msg )

+update : Msg -> Model -> ( Model, Testable.Cmd.Cmd Msg )

 update msg model =

@@ -44,7 +45,7 @@ update msg model =

             ( Model model.apiKey model.topic (Maybe.withDefault model.gifUrl maybeUrl)

-            , Cmd.none

+            , Testable.Cmd.none

             )

@@ -89,7 +90,7 @@ imgStyle url =

 

-getRandomGif : String -> String -> Cmd Msg

+getRandomGif : String -> String -> Testable.Cmd.Cmd Msg

 getRandomGif apiKey topic =

     Http.get decodeUrl (randomUrl apiKey topic)

         |> Task.perform (always Nothing >> NewGif)

diff --git b/examples/Main.elm a/examples/Main.elm

@@ -3,12 +3,13 @@ module Main exposing (..)

 import Task

+import Testable

 

 main =

     Html.App.program

-        { init = init "__API_KEY__" "funny cats"

-        , update = update

+        { init = Testable.init <| init "__API_KEY__" "funny cats"

+        , update = Testable.update update

         , view = view

```

## Example tests

Here is an example of the types of tests you can write for testable components:

```elm

import ElmTest exposing (..)

import Testable.TestContext exposing (..)

import Testable.Effects as Effects

import Testable.Http as Http

myComponent =

    { init = MyComponent.init

    , update = MyComponent.update

    }

all : Test

all =

    suite "MyComponent"

        [ myComponent

            |> startForTest

            |> currentModel

            |> assertEqual (Ok expectedModelValue)

            |> test "sets initial state"

        , myComponent

            |> startForTest

            |> assertHttpRequest (Http.getRequest "https://example.com/myResource")

            |> test "makes initial HTTP request"

        , myComponent

            |> startForTest

            |> resolveHttpRequest (Http.getRequest "https://example.com/myResource")

                (Http.ok """{"data":"example JSON response"}""")

            |> assertEqual (Ok expectedModelValue)

            |> test "updated the model on HTTP success"

        , myComponent

            |> startForTest

            |> update (MyComponent.LoadDetails 1234)

            |> assertHttpRequest (Http.getRequest "https://example.com/myResource/1234")

            |> test "pressing the button makes a new HTTP request"

        ]

```

Here are [complete tests for the RandomGif example](https://github.com/avh4/elm-testable/blob/master/examples/tests/RandomGifTests.elm).

## Example integration with `Main`

To convert your testable `view` and `update` functions into functions that work with `StartApp`, use the `Testable` module:

```elm

main : Program Never

main =

    Html.App.program

        { init = Testable.init MyComponent.init

        , update = Testable.update MyComponent.update

        , view = MyComponent.view

        , subscriptions = MyComponent.subscriptions

        }

```