A TestContext represents an Elm program, a current state for that program, and a log of any errors that have occurred while simulating interaction with the program.

• To create a TestContext, see thecreate*` functions below.
• To advance the state of a TestContext, see Simulating user input, and Directly sending Msgs
• To assert on the resulting state of a TestContext, see Final assertions

Creates a TestContext from the parts of a standard Html.program.

See other create* functions below if the program you want to test uses flags or nagivation.

Creates a TestContext from the parts of a standard with flags (Html.programWithFlags).

If your program uses Json.Encode.Value as its flags type, you may find createWithJsonStringFlags useful.

If your program does not use flags, see create.

See other create* functions below if the program you want to test uses nagivation.

A simplified way to create a TestContext for a program that decodes its flags with a JSON decoder.

If your program does not use Json.Encode.Value as its flags type, or you want more control over how the flags are provided in your tests, see createWithFlags.

If your program does not use flags, see create.

See other create* functions below if the program you want to test uses nagivation.

Creates a TestContext from the parts of a Navigation.program.

See other create* functions above and below if the program you want to test uses flags or does not use nagivation.

Creates a TestContext from the parts of a program with navigation and flags (Navigation.programWithFlags).

If your program uses Json.Encode.Value as its flags type, you may find createWithNavigationAndJsonStringFlags useful.

If your program does not use flags, see createWithNavigation.

If your program does not use navigation, see createWithFlags.

A simplified way to create a TestContext for a program with navigation that decodes its flags with a JSON decoder.

If your program does not use Json.Encode.Value as its flags type, or you want more control over how the flags are provided in your tests, see createWithNavigationAndFlags.

If your program does not use flags, see createWithNavigation.

If your program does not use navigation, see createWithJsonStringFlags.

Simulates clicking a button.

Currently, this function will find and click a <button> HTML node containing the given buttonText.

NOTE: In the future, this function will be generalized to find buttons with accessibility attributes matching the given buttonText.

Simulates a custom DOM event.

NOTE: If there is another, more specific function (see Simulating user input that does what you want, prefer that instead, as you will get the benefit of better error messages.

Parameters:

• findTarget: A function to find the HTML element that responds to the event (typically this will be a call to Test.Html.Query.find [ ...some selector... ])
• ( eventName, eventValue ): The event to simulate (see Test.Html.Event "Event Builders")

url may be an absolute URL or relative URL

Advances the state of the TestContext's program by using the TestContext's program's update function with the given msg.

This can be used to simulate events that can only be triggered by commands (Cmd) and subscriptions (Sub) (i.e., that cannot be triggered by user interaction with the view).

NOTE: When possible, you should prefer Simulating user input, as doing so will make your tests more robust to changes in your program's implementation details.

A simpler way to assert that a TestContext's view matches a given selector.

expectViewHas [...selector...] is the same as expectView (Test.Html.Query.has [...selector...]).

Makes an assertion about the current state of a TestContext's view.

Makes an assertion about the last effect produced by a TestContext's program.

Make an assertion about the current state of a TestContext's model.

shouldHave [...selector...] is equivalent to shouldHaveView (Test.Html.Query.has [...selector...])

shouldNotHave [...selector...] is equivalent to shouldHaveView (Test.Html.Query.hasNot [...selector...])

Validates the the current state of a TestContext's view without ending the TestContext.

Validates the last effect produced by a TestContext's program without ending the TestContext.

Ends a TestContext, reporting any errors that occurred.

NOTE: You should prefer using a final assertion to end your test over using done, as doing so will make the intent of your test more clear.

fail can be used to report custom errors if you are writing your own convenience functions to deal with test contexts.

Example (this is a function that checks for a particular structure in the program's view, but will also fail the TestContext if the expectedCount parameter is invalid):

expectNotificationCount : Int -> TestContext Msg Model effect -> TestContext Msg Model effect
expectNotificationCount expectedCount testContext =
    if expectedCount <= 0 then
        testContext
            |> TestContext.fail "expectNotificationCount"
                ("expectedCount must be positive, but was: " ++ toString expectedCount)
    else
        testContext
            |> shouldHave
                [ Test.Html.Selector.class "notifications"
                , Test.Html.Selector.text (toString expectedCount)
                ]