Scala example source code file (OneAndTest.scala)

This example Scala source code file (OneAndTest.scala) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Scala by Example" ^TM.

Learn more about this Scala project at its project page.

Java - Scala tags/keywords

applicative, equal, foldable, foldable1, functor, int, list, nel, nonemptylist, oneand, option, plus, some, traverse1

The OneAndTest.scala Scala example source code

package scalaz

import org.scalacheck.Prop.{exists, propBoolean}

import scalaz.scalacheck.ScalazProperties._
import scalaz.scalacheck.ScalazArbitrary._
import std.AllInstances._
import OneAnd.oneAndNelIso
import org.scalacheck.Prop.forAll

object OneAndTest extends SpecLite {
  type OneAndOption[A] = OneAnd[Option, A]
  type OneAndList[A] = OneAnd[List, A]
  type OneAndNel[A] = OneAnd[NonEmptyList, A]

  checkAll("OneAnd", equal.laws[OneAnd[List, Int]])
  checkAll("OneAnd", order.laws[OneAnd[List, Int]])
  checkAll("OneAnd List", monad.laws[OneAndList])
  checkAll("OneAnd Option", monad.laws[OneAndOption])
  checkAll("OneAnd Nel", plus.laws[OneAndNel])
  checkAll("OneAnd List", traverse1.laws[OneAndList])
  checkAll("OneAnd Nel", traverse1.laws[OneAndNel])
  checkAll("OneAnd List", zip.laws[OneAndList])
  checkAll("OneAnd Nel", zip.laws[OneAndNel])
  checkAll("OneAnd List", align.laws[OneAndList])
  checkAll("OneAnd Nel", align.laws[OneAndNel])
  checkAll("OneAnd List", semigroup.laws[OneAnd[List, Int]])
  checkAll("OneAnd Nel", semigroup.laws[OneAnd[NonEmptyList, Int]])
  checkAll("OneAnd Option", semigroup.laws[OneAnd[Option, Int]])

  checkAll(FoldableTests.anyAndAllLazy[OneAndList])

  "findLeft/findRight" in {
    val a = OneAnd(1, List(2, 3, 4, 5))
    Foldable[OneAnd[List, ?]].findLeft(a)(_ % 2 == 0) must_=== Some(2)
    Foldable[OneAnd[List, ?]].findRight(a)(_ % 2 == 0) must_=== Some(4)
  }

  "findLeft" ! forAll{ a: OneAnd[List, Int] =>
    val f = (_: Int) % 3 == 0
    val F = Foldable[OneAnd[List, ?]]
    F.findLeft(a)(f) must_=== Foldable[IList].findLeft(F.toIList(a))(f)
  }

  "findRight" ! forAll { a: OneAnd[List, Int] =>
    val f = (_: Int) % 3 == 0
    val F = Foldable[OneAnd[List, ?]]
    F.findRight(a)(f) must_=== Foldable[IList].findRight(F.toIList(a))(f)
  }

  "oneAndNelIso is iso" ! forAll {(nel: NonEmptyList[Int]) =>
    oneAndNelIso.from(oneAndNelIso.to(nel)) must_===(nel)
  }

  "fold1 on fold0" ! forAll {(ints: OneAnd[List, Int]) =>
    val lst = ints.head :: ints.tail
    Foldable[OneAndList].foldMap(ints)(_ + 1) must_===(lst.size + lst.sum)
    Foldable1[OneAndList].foldMap1(ints)(_ + 1) must_===(lst.size + lst.sum)
  }

  "fold1 on fold1" ! forAll {(ints: OneAnd[NonEmptyList, Int]) =>
    val lst = ints.head :: ints.tail.list
    Foldable[OneAndNel].foldMap(ints)(_ + 1) must_===(lst.count(_ => true) + lst.toList.sum)
    Foldable1[OneAndNel].foldMap1(ints)(_ + 1) must_===(lst.count(_ => true) + lst.toList.sum)
  }

  "right fold1 on fold" ! forAll {(ints: OneAnd[List, Int]) =>
    val lst = ints.head :: ints.tail
    val llst = Functor[OneAndList].map(ints)(List(_))
    Foldable[OneAndList].foldRight(ints, List.empty[Int])(_ :: _) must_===(lst)
    Foldable1[OneAndList].foldRight1(llst)(_ ++ _) must_===(lst)
  }

  "right fold1 on fold1" ! forAll {(ints: OneAnd[NonEmptyList, Int]) =>
    val lst = ints.head :: ints.tail.list.toList
    val llst = Functor[OneAndNel].map(ints)(List(_))
    Foldable[OneAndNel].foldRight(ints, List.empty[Int])(_ :: _) must_===(lst)
    Foldable1[OneAndNel].foldRight1(llst)(_ ++ _) must_===(lst)
  }

  "traverse1 on traverse" ! forAll {(ints: OneAnd[List, Int], f: Int => List[Int]) =>
    (Traverse1[OneAndList].traverse1(ints)(f)
       must_==(Traverse[OneAndList].traverse(ints)(f)))
  }

  implicit def OneAndNelEqual[A](implicit E: Equal[IList[A]]): Equal[NonEmptyList[OneAndNel[A]]] = new Equal[NonEmptyList[OneAndNel[A]]] {
    override def equal(a: NonEmptyList[OneAndNel[A]], b: NonEmptyList[OneAndNel[A]]): Boolean =
      Equal[IList[A]].equal(a.map(oa => oa.head +: oa.tail.list).list.flatten, b.map(bb => bb.head +: bb.tail.list).list.flatten)
  }

  "traverse1 on traverse1" ! forAll {(ints: OneAnd[NonEmptyList, Int],
                                    f: Int => NonEmptyList[Int]) =>
    (Traverse1[OneAndNel].traverse1(ints)(f)
       must_===(Traverse[OneAndNel].traverse(ints)(f)))
  }

  "inequality exists" ! forAll {(a: OneAnd[List, Int]) =>
    exists {(b: OneAnd[List, Int]) =>
      propBoolean(!Equal[OneAndList[Int]].equal(a, b))
    }
  }

  object instances {
    def functor[F[_]: Functor] = Functor[OneAnd[F, ?]]
    def functorMax[F[_]: MonadPlus: Traverse1] = Functor[OneAnd[F, ?]]
    def apply[F[_]: Applicative: Plus] = Apply[OneAnd[F, ?]]
    def applicative[F[_]: ApplicativePlus] = Applicative[OneAnd[F, ?]]
    def bind[F[_]: Monad: Plus] = Bind[OneAnd[F, ?]]
    def monad[F[_]: MonadPlus] = Monad[OneAnd[F, ?]]
    def plus[F[_]: Applicative: Plus] = Plus[OneAnd[F, ?]]
    def foldable[F[_]: Foldable] = Foldable1[OneAnd[F, ?]]
    def foldable1[F[_]: Foldable1] = Foldable1[OneAnd[F, ?]]
    def traverse[F[_]: Traverse] = Traverse1[OneAnd[F, ?]]
    def traverse1[F[_]: Traverse1] = Traverse1[OneAnd[F, ?]]
    def semigroup[F[_]: Applicative: Plus, A] = Semigroup[OneAnd[F, A]]
  }
}