Test views by writing expectations about Html values.
import Html
import Html.Attributes exposing (class)
import Test exposing (test)
import Test.Html.Query as Query
import Test.Html.Selector exposing (text, tag)
test "Button has the expected text" <|
\() ->
Html.div [ class "container" ]
[ Html.button [] [ Html.text "I'm a button!" ] ]
|> Query.fromHtml
|> Query.find [ tag "button" ]
|> Query.has [ text "I'm a button!" ]These tests are designed to be written in a pipeline like this:
- Call
Query.fromHtmlon yourHtmlto begin querying it. - Use queries like
Query.find,Query.findAll, andQuery.childrento find the elements to test. - Create expectations using things like
Query.hasandQuery.count.
These are normal expectations, so you can use them with fuzz just as easily as with test!
Queries come in two flavors: Single and Multiple.
This is because some queries are expected to return a single result, whereas others may return multiple results.
If a Single query finds exactly one result, it will succeed and continue with
any further querying or expectations. If it finds zero results, or more than one,
the test will fail.
Since other querying and expectation functions are written in terms of Single
and Multiple, the compiler can help make sure queries are connected as
expected. For example, count accepts a Multiple, because counting a single element does not make much sense!
If you have a Multiple and want to use an expectation that works on a Single,
such as Query.has, you can use Query.each to run the expectation on each of the elements in the Multiple.
Ordinary Html.Attribute msg values can be used to select elements using
Test.Html.Selector.attribute. It is important when using this selector to
understand its behavior.
-
Html.Attributes.classandHtml.Attributes.classListwill work the same asTest.Html.Selector.classes, matching any element with at least the given classes. This behavior echoes that ofelement.querySelectorAll('.my-class')from JavaScript, where any element with at least.my-classwill match the query. -
Html.Attributes.stylewill work the same way asTest.Html.Selector.styles, matching any element with at least the given style properties. -
Any other
Stringattributes and properties liketitle, orBoolattributes likedisabledwill match elements with the exact value for those attributes. -
Any attributes from
Html.Events, or attributes with values that have types other thanStringorBoolwill not match anything.
The example below demonstrates usage
import Html
import Html.Attributes as Attr
import Test exposing (test, describe)
import Test.Html.Query as Query
import Test.Html.Selector exposing (attribute, text)
tests =
describe "attributes"
[ test "the welcome <h1> says hello!" <|
\() ->
Html.div [] [ Html.h1 [ Attr.title "greeting" ] [ Html.text "Hello!" ] ]
|> Query.fromHtml
|> Query.find [ attribute <| Attr.title "greeting" ]
|> Query.has [ text "Hello!" ]
, test "the .Hello.World div has the class Hello" <|
\() ->
Html.div
[ Attr.classList
[ ( True, "Hello" )
, ( True, "World" )
]
]
|> Query.fromHtml
|> Query.find
[ attribute <|
Attr.classList [ ( True, Hello ) ]
]
, test "the header is red" <|
\() ->
Html.header
[ Attr.style
[ ( "backround-color", "red" )
, ( "color", "yellow" )
]
]
|> Query.fromHtml
|> Query.find
[ attribute <|
Attr.style [ ( "backround-color", "red" ) ]
]
]| Version | Notes |
|---|---|
| 5.1.2 | Fix bug with mapped and lazy views |
| 5.1.1 | Fix children |
| 5.1.0 | Add filtermap |
| 5.0.1 | Fix bug with lazy views |
| 5.0.0 | Allow querying by attributes |
| 4.1.0 | Query styles |
| 4.0.0 | Allow custom events |
| 3.0.0 | Allow events to be testable |
| 2.0.0 | Better support for events by @rogeriochaves |
| 1.1.0 | Support for events by @rogeriochaves |
| 1.0.0 | Initial release |