Generation of arbitrary case classes / ADTs instances with scalacheck and shapeless

Add to your build.sbt

libraryDependencies += "com.github.alexarchambault" %% "scalacheck-shapeless_1.18" % "1.3.2"

scalacheck-shapeless depends on shapeless 2.3 and scalacheck 1.18. It is built against scala 2.12, and 2.13.

Import the content of org.scalacheck.ScalacheckShapeless close to where you want Arbitrary type classes to be automatically available for case classes / sealed hierarchies,

import org.scalacheck.ScalacheckShapeless._
//  If you defined:
// case class Foo(i: Int, s: String, blah: Boolean)
// case class Bar(foo: Foo, other: String)
// sealed trait Base
// case class BaseIntString(i: Int, s: String) extends Base
// case class BaseDoubleBoolean(d: Double, b: Boolean) extends Base
//  then you can now do
implicitly[Arbitrary[Foo]]
implicitly[Arbitrary[Bar]]
implicitly[Arbitrary[Base]]

and in particular, while writing property-based tests,

property("some property about Foo") {
  forAll { foo: Foo =>
    // Ensure foo has the required property
  }
}

without having to define yourself an Arbitrary for Foo.

• cats-check, a library providing cats type class instances for ScalaCheck type classes,
• scalacheck-datetime, a library to deal with datetimes with scalacheck,
• scalacheck-extensions, a macro-based automatic Arbitrary generation (discontinued?).

Released under the Apache 2 license. See LICENSE file for more details.

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