Oh, I have figured it out myself.
I can use helpers from play.test.Helpers
then I use them with specs2 matchers and it works as intended.
import controllers.routes
import org.specs2.mutable.Specification
import play.test.Helpers._
import play.api.test._
class MyControllerSpec extends Specification {
"My Controller" should {
"respond with text/plain content type" in new WithApplication {
val result = callAction(routes.ref.MyController.index(), fakeRequest())
contentType(result) mustEqual "text/plain"
}
}
}