Spec

Functions for writing specs.

A spec is a collection of scenarios, each of which provides an example that illustrates a behavior belonging to your program. Each scenario follows the same basic plan:

Configure the initial state of the world (and your program).
Perform a sequence of steps.
Check your xpectations about the new state of the world after the steps have been performed.

Here's a sample spec for a browser program called App:

Spec.describe "some part of my system"
[ Spec.scenario "the awesome path" (
    Spec.given (
      Spec.Setup.init (App.init testFlags)
        |> Spec.Setup.withView App.view
        |> Spec.Setup.withUpdate App.update
    )
    |> Spec.when "something happens"
      [ Spec.Markup.target << by [ id "some-button" ]
      , Spec.Markup.Event.click
      ]
    |> Spec.it "does the right thing" (
      Spec.Markup.observeElement
        |> Spec.Markup.query << by [ id "some-words" ]
        |> Spec.expect (Spec.Markup.hasText "something awesome")
    )
  )
]

Creating a Spec

type alias Spec model msg =

Spec model msg

Represents the spec.

type Scenario model msg

Represents a particular scenario in a spec.

describe : String -> List (Scenario model msg) -> Spec model msg

Specify a description and a list of scenarios that compose the spec.

scenario : String -> Plan model msg -> Scenario model msg

Create a scenario with a description and a plan.

Creating the Scenario Script

type Script model msg

Represents the setup and steps involved in a scenario.

given : Setup model msg -> Script model msg

Provide the Setup that represents the state of the world at the start of the scenario.

See Spec.Setup for functions to construct this representation.

when :

String

-> List (Context model -> Command msg)

-> Script model msg

Specify a description and the steps involved in a scenario.

Each step is a function from Step.Context to Step.Command, but usually you will use steps that are provided by other modules, like Spec.Markup.Event.

You may provide multiple when blocks as part of a scenario.

Turn a Script into a Plan

type Plan model msg

Represents the full plan (setup, steps, expectations) involved in a scenario.

it : String -> Expectation model -> Script model msg -> Plan model msg

Specify an expectation to be checked once the scenario's steps have been performed.

observeThat :

List (Script model msg -> Plan model msg)

-> Script model msg

-> Plan model msg

Specify multiple expectations to be checked once the scenario's steps have been performed.

expect : Claim a -> Observer model a -> Expectation model

Provide an observer with a claim to evaluate.

Tag a Scenario

tagged : List String -> Scenario model msg -> Scenario model msg

Associate one or more tags with a scenario.

When you run the spec suite with specific tags specified, only the scenarios tagged with those tags will be executed.

brian-watkins/elm-spec/1.1.0

Spec

Creating a Spec

Creating the Scenario Script

Turn a Script into a Plan

Tag a Scenario

Modules