home | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Scala example source code file (OptionalTest.scala)

This example Scala source code file (OptionalTest.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

eitherint, equal, int, option, optional, sfa, show, validation, vstring, vstringnel

The OptionalTest.scala Scala example source code

package scalaz

import Scalaz.Id
import std.AllInstances._

object OptionalTest extends SpecLite {

  def definedTests[F[_],A](context: F[A], value: A, default: => A, alternative: => F[A])(implicit O: Optional[F], EA: Equal[A], EFA: Equal[F[A]], SA: Show[A], SFA: Show[F[A]]) = {
    O.getOrElse(context)(default)  must_===(value)
    O.isDefined(context)           must_===(true)
    O.orElse(context)(alternative) must_===(context)
    O.nonEmpty(context)            must_===(true)
    O.isEmpty(context)             must_===(false)
    O.?(context)(1,0)              must_===(1)
    O.toOption(context)            must_===(Option(value))
    O.toMaybe(context)             must_===(Maybe.just(value))
  }

  def undefinedTests[F[_],A](context: F[A], default: A, alternative: F[A])(implicit O: Optional[F], EA: Equal[A], EFA: Equal[F[A]], SA: Show[A], SFA: Show[F[A]]) = {
    O.getOrElse(context)(default)  must_===(default)
    O.isDefined(context)           must_===(false)
    O.orElse(context)(alternative) must_===(alternative)
    O.nonEmpty(context)            must_===(false)
    O.isEmpty(context)             must_===(true)
    O.?(context)(1,0)              must_===(0)
    O.toOption(context)            must_===(Option.empty[A])
    O.toMaybe(context)             must_===(Maybe.empty[A])
  }

  """\/ instance tests""" in {
    type EitherInt[A] = Int \/ A

    def right(a: Int): EitherInt[Int] = \/.right(a)
    def left(a: Int): EitherInt[Int] = \/.left(a)

    definedTests(right(1), 1, 0, right(0))
    undefinedTests(left(0), 0, right(0))
  }

  // currently there are no Equal[LazyEither], Show[LazyEither]
//  """LazyEither instance tests""" in {
//    type LEInt[A] = LazyEither[Int,A]
//    def right(a: Int): LEInt[Int] = LazyEither.lazyRight(a)
//    def left(a: Int): LEInt[Int] = LazyEither.lazyLeft(a)
//    definedTests(right(1), 1, 0, right(0))
//    undefinedTests(left(0), 0, right(0))
//  }

  // currently there is no Show[LazyOption]
//  "LazyOption instance tests" in {
//    definedTests(LazyOption.lazySome(1), 1, 0, LazyOption.lazySome(0))
//    undefinedTests(LazyOption.lazyNone[Int], 0, LazyOption.lazySome(0))
//  }

  "Option instance tests" in {
    definedTests(Option(1), 1, 0, Option(0))
    undefinedTests(Option.empty[Int], 0, Option(0))
  }

  """Validation instance tests""" in {
    type VString[A] = Validation[String,A]

    def success(a: Int): VString[Int] = Validation.success(a)
    def failure(s: String): VString[Int] = Validation.failure(s)

    definedTests[VString, Int](success(1), 1, 0, success(0))
    undefinedTests[VString, Int](failure("oO"), 0, success(0))
  }

  """ValidationNel instance tests""" in {
    type VStringNel[A] = ValidationNel[String, A]

    def successNel(a: Int): VStringNel[Int] = Validation.success(a)
    def failureNel(s: String): VStringNel[Int] = Validation.failureNel(s)

    definedTests[VStringNel, Int](successNel(1), 1, 0, successNel(0))
    undefinedTests[VStringNel, Int](failureNel("oO"), 0, successNel(0))
  }

  "Id instance tests" in {
    definedTests[Id, Int](1, 1, 0, 0)
  }

  "Maybe instance tests" in {
    definedTests(Maybe.just(1), 1, 0, Maybe.just(0))
    undefinedTests(Maybe.empty[Int], 0, Maybe.just(0))
  }

  "syntax test" in {
    import syntax.optional._

    val value = Option(1)

    ( value.getOrElse(0)      ) must_===(1)
    ( value.isDefined         ) must_===(true)
    ( value.orElse(Option(0)) ) must_===(value)
    ( value.nonEmpty          ) must_===(true)
    ( value.isEmpty           ) must_===(false)
    ( value ? 1 | 0           ) must_===(1)
    ( value.toOption          ) must_===(value)
  }

}

Other Scala examples (source code examples)

Here is a short list of links related to this Scala OptionalTest.scala source code file:



my book on functional programming

 

new blog posts

 

Copyright 1998-2019 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.