witchy ScalaCheck examples

gistfile1.scala

import org.scalacheck.Prop.forAll
import org.scalacheck.Properties

object ShakespeareSpec extends Properties("Bubble") {
  
  def spell(words: List[String], mysticNumber: Int) = 
    mysticNumber.toString +
      words.mkString + "toil" + "trouble"
      
  property("bubble") = forAll { (a: List[String], b: Int) =>
    spell(a, b).length ==
      Math.ceil(Math.log10(b + 1)) + a.map(_.length).sum + 11
  }
}

[info] ! Bubble.bubble: Falsified after 2 passed tests.
[info] > ARG_0: List("")
[info] > ARG_0_ORIGINAL: List("漢字")
[info] > ARG_1: 0
[info] > ARG_1_ORIGINAL: -677524853
[error] Failed: Total 1, Failed 1, Errors 0, Passed 0

gistfile2.scala

//everyone knows magic numbers are always positive!
forAll(listOf(alphaStr), posNum[Int]) { (a, b) =>
    spell(a, b).length ==
      Math.ceil(Math.log10(b + 1)) + a.map(_.length).sum + 11
  }

gistfile3.scala

forAll(Gen.choose(1, 10)) { magicNumber =>
  magicNumber.invoke == motherHecate
}

forAll(Gen.oneOf(eyeOfNewt, toeOfFrog, wingOfBat)) { ingredient => 
  ingredient.addToCauldron == hellBroth
}

forAll(Gen.someOf(tongueOfDog, addresFork, blindwormsSting,
                  lizardsLeg, howletsWing)) { ingredients =>
  boil(ingredients.map(_.addToCauldron)) == charmOfPowerfulTrouble
}

val slimy = Gen.oneOf(eyeOfNewt, toeOfFrog, lizardsLeg)
val crawly = Gen.oneOf(addersFork, blindwormsSting, lizardsLeg)
val creepy = Gen.oneOf(wingOfBat, tongueOfDog, howletsWing)

forAll(Gen.someOf(slimy, crawly, creepy)) { ingredients =>
  boil(ingredients.map(_.addToCauldron)) == charmOfPowerfulTrouble
}

forAll(Gen.listOf(slimy)) { ingredients =>
  touch(ingredients) == skinCrawl
}

gistfile4.scala

val spellGen = arbitrary[String].map(_ + ", so mote it be")

val titleGen = arbitrary[String].flatMap{ name =>
  Gen.oneOf("East", "West", "North", "South").map { dir =>
    name + ", Wicked Witch of the " + dir
  }
}

case class Spell(ingredients: List[(Int, Ingredient)], boilingTime: Int)

val spellRecipeGen = for {
  ingredientList <- Gen.someOf(slimy, crawly, creepy)
  amounts <- Gen.listOfN(ingredientList.length, Gen.choose(1, 10))
  bubblesFor <- Gen.posNum[Int].suchThat(_ < 720)
} yield {
  Spell(amounts.zip(ingredientList), bubblesFor)
}

gistfile5.scala

forAll { p: Prince =>
  princessKiss(turnIntoFrog(p)) == p
}