Using Scala-js

ScalaTest 3.2.18 includes support for Scala-js. Following the steps in the Scala-js Basic Tutorial, you'll add the following to sbt build file to use ScalaTest:

libraryDependencies += "org.scalatest" %%% "scalatest" % "3.0.0" % "test"

The following is an example test suite written using ScalaTest:

package tutorial.webapp

import org.scalatest._
import org.scalajs.jquery.jQuery

class TutorialTestWithScalaTest extends AnyFunSpec {

  // Initialize App
  TutorialApp.setupUI()

  describe("TutorialApp") {
    it("should contain 'Hello World' text in its body") {
      assert(jQuery("p:contains('Hello World')").length == 1)
    }

    it("should append 'You clicked the button!' text when the user clicks on the 'Click me!' button") {
      def messageCount =
        jQuery("p:contains('You clicked the button!')").length

      val button = jQuery("button:contains('Click me!')")
      assert(button.length == 1)
      assert(messageCount == 0)

      for (c <- 1 to 5) {
        button.click()
        assert(messageCount == c)
      }
    }

  }
}

The first test uses jQuery to verify that the page contains exactly one <p> element containing the text “Hello World” after the UI has been set up. The second test checks the behavior that when 'Click me!' button is clicked, it will append a new <p> element containing the text “Hello World” in the body of the page.

You can run the test by issuing test command in the sbt:

> test
[info] TutorialTestWithScalaTest:
[info] TutorialApp
[info] - should contain 'Hello World' text in its body
[info] - should append 'You clicked the button!' text when the user clicks on the 'Click me!' button

Now we can take a look at some goodies ScalaTest has that can help you address specific problems, starting with using Inside.