Ruslan Batdalov Ruslan Batdalov - 1 month ago 7
Scala Question

How to combine WithApplication(Loader) and ExecutionEnv

I am writing Specs2 tests for methods returning futures in a project using Scala and Play framework. Documentation and answers to this question recommend using the await modifier, which requires to add implicit ExecutionEnv. A minimal working example (adapted from one of the mentioned answers):

class FutureSpec extends mutable.Specification {
"Even in future one" should {
"be greater than zero" in { implicit ee: ExecutionEnv =>
Future(1) must be_>(0).await
}
}
}


But some of my tests require WithApplicationLoader. If I add it to the example, it does not compile:

class FutureSpec extends mutable.Specification {
"Even in future one" should {
"be greater than zero" in new WithApplicationLoader { implicit ee: ExecutionEnv =>
Future(1) must be_>(0).await
}
}
}


WithApplication instead of WithApplicationLoader has exactly the same effect (expectedly).

Is it possible to use WithApplicationLoader together with implicit ExecutionEnv?

Unfortunately, the second option described in the documentation -- moving ExecutionEnv to the class constructor instead of a particular method -- is not available. This specification:

class FutureSpec(implicit ee: ExecutionEnv) extends mutable.Specification {
"Even in future one" should {
"be greater than zero" in new WithApplicationLoader {
Future(1) must be_>(0).await
}
}
}


works, but it is ignored by IntelliJ Idea (I can run such a specification separately, but the configuration running all tests in the project does not execute it).

Answer

This works for me with IntelliJ 2016.1.3:

import play.api.test.{PlaySpecification, WithApplication}
import org.specs2.concurrent.ExecutionEnv
import scala.concurrent.Future

class FutureSpec extends PlaySpecification {
  implicit val ee = ExecutionEnv.fromGlobalExecutionContext
//  // or this:
//  implicit val ee = ExecutionEnv.fromExecutionContext(play.api.libs.concurrent.Execution.Implicits.defaultContext)

  "Even in future one" should {
    "be greater than zero" in new WithApplication {
      Future(1) must be_>(0).await
    }
  }
}

Here is my build.sbt:

name := "throwaway"

version := "1.0"

scalaVersion := "2.11.8"

libraryDependencies += "org.specs2" %% "specs2-core" % "3.8.5.1" % "test"

libraryDependencies += "com.typesafe.play" %% "play" % "2.5.9" % "test"

libraryDependencies += "com.typesafe.play" %% "play-specs2" % "2.5.9" % "test"

libraryDependencies += "com.typesafe.play" %% "play-test" % "2.5.9" % "test"