Scala example source code file (TagTest.scala)

This example Scala source code file (TagTest.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

int, list, monoid, mult, semigroup, show, speclite, tag, tagtest

The TagTest.scala Scala example source code

package scalaz

import scalaz.scalacheck.ScalazArbitrary._
import std.AllInstances._

import Tags.{Multiplication => Mult}
import org.scalacheck.Prop.forAll

object TagTest extends SpecLite {
  "of.subst" should {
    "substitute" ! forAll {xs: List[Int] =>
      (Tag unwrap Foldable[List].fold(Tag.of[Mult].subst(xs))
         must_===(xs.foldLeft(1)(_ * _)))
    }
  }

  "of.onF" should {
    "substitute" ! forAll {xs: List[List[Unit]] =>
      (Tag unwrap (Foldable[List].foldMap(xs)(Tag.of[Mult].onF(_.length)))
         must_===(xs.foldLeft(1)((n, l) => n * l.length)))
    }
  }

  "of.onCov" should {
    "choose covariant position" in {
      Tag.of[Mult].onCov((a:Int) => a): (Int => (Int @@ Mult))
      true
    }
  }

  "of.onContra" should {
    "choose contravariant position" in {
      Tag.of[Mult].onContra(Show[Int]): Show[Int @@ Mult]
      true
    }
  }

  "of.unsubst" should {
    "substitute" in {
      Tag.of[Mult].unsubst(Semigroup[Int @@ Mult]): Semigroup[Int]
      true
    }
  }

  "of.unapply" should {
    "support unwrapping in pattern match" in {
      Monoid[Int @@ Mult].append(Mult(3), Mult(3)) match {
        case Mult(9) ⇒ true
        case Mult(_) ⇒ false
      }
    }
  }
}