P06Spec.scala

 def takeWhileRec(function: (Int) => Boolean, list:List[Int]):List[Int] = list match {
      case Nil => Nil
      case head :: tail => if (function(head)) head +: takeWhileRec(function,tail) else Nil
    }

  "takeWhile" should {
    "work the same" in {
      val function: (Int) => Boolean = _ < 3
      val list: List[Int] = List(1, 2, 3)
      takeWhileRec(function,list) === list.takeWhile(function)
    }
  }