Functional testing

Let's look at some of Play's test cases to see how to use the helper methods. For example, consider the DevErrorPageSpec test, which is defined as follows:

object DevErrorPageSpec extends PlaySpecification{

  "devError.scala.html" should {

    val testExceptionSource = new play.api.PlayException.ExceptionSource("test", "making sure the link shows up") {
      ...
    }
    ….
    "show prod error page in prod mode" in {
      val fakeApplication = new FakeApplication() {
        override val mode = play.api.Mode.Prod
      }
      running(fakeApplication) {
        val result = DefaultGlobal.onError(FakeRequest(), testExceptionSource)
        Helpers.contentAsString(result) must contain("Oops, an error occurred")
      }
    }
  }
}

This test starts FakeApplication with the Prod mode and checks the response when FakeRequest encounters an exception.

FakeApplication extends an application and is defined...