izumi.distage.testkit.scalatest

 trait PetStore[F[_, _]] {
   def purchasePet(name: String, cost: Int): F[Throwable, Boolean]
 }

 trait Pets[F[_, _]]
   def myPets: F[Throwable, List[String]]
 }

 val store = new PetStore[ZIO[PetStore[IO], _, _]] {
   def purchasePet(name: String, cost: Int): RIO[PetStore[IO], Boolean] = ZIO.accessM(_.get.purchasePet(name, cost))
 }
 val pets = new Pets[ZIO[Pets[IO], _, _]] {
   def myPets: RIO[Pets[IO], List[String]] = ZIO.accessM(_.get.myPets)
 }

 "test purchase pets" in {
   for {
     _
     for {
       _    <- store.purchasePet("Zab", cost = 213)
       pets <- pets.myPets
       _    <- assertIO(pets.contains("Zab"))
     } yield ()
     // : ZIO[PetsEnv, Throwable, Unit]
 }