mrdziuban / scalacheck-magnolia   0.0.4

Apache License 2.0 GitHub

Scalacheck Arbitrary derivation using magnolia

Scala versions: 2.12 2.11
Scala.js versions: 0.6

Deprecation Notice

This library is deprecated and no longer kept up to date or otherwise maintained. Consider using magnolify-scalacheck module instead.


scalacheck-magnolia performs generic derivation of scalacheck Arbitrary instances for product and sum types, i.e. case classes and ADTs, using Magnolia. Much of the code was inspired by scalacheck-shapeless, which I've found to work reliably, but cause huge compile time increases, especially for deeply nested case classes.


Add to your build.sbt:

resolvers += "mrdziuban-maven" at ""
libraryDependencies += "com.mrdziuban" %% "scalacheck-magnolia" % "0.5.0"

This will pull in scalacheck 1.15.4 and magnolia 0.17.0.

To materialize Arbitrary instances for your case classes or sealed traits, import com.mrdziuban.ScalacheckMagnolia._. Magnolia can derive Arbitrary instances for case classes

import com.mrdziuban.ScalacheckMagnolia._
import org.scalacheck.Arbitrary

case class Test(i: Int, b: Boolean, s: String)


as well as for sealed traits

sealed trait Foo
case object Bar extends Foo
case class Baz(s: String) extends Foo


It can be used in scalacheck property tests like so:

import org.scalacheck.Prop.forAll

forAll((_: Test) => true /* check some properties of Test */)


Released under the Apache 2.0 license. See the LICENSE file for more details.