Added Scalacheck Arbitrary implementations for Natural and NonEmptyList.

bakeemawaytoys · jbgi · commit 405c3ec31351 · 2017-05-10T21:55:58.000+02:00
diff --git a/props-core-scalacheck/src/main/scala/fj/data/ArbitraryNatural.scala b/props-core-scalacheck/src/main/scala/fj/data/ArbitraryNatural.scala
@@ -0,0 +1,13 @@
+package fj.data
+
+import org.scalacheck.Arbitrary
+
+/**
+  * A Scalacheck [[Arbitrary]] for [[Natural]].
+  */
+object ArbitraryNatural {
+
+  implicit def arbitraryNatural: Arbitrary[Natural] =
+    Arbitrary(Arbitrary.arbBigInt.arbitrary.map(_.abs).map(bi => Natural.natural(bi.bigInteger).some()))
+
+}
diff --git a/props-core-scalacheck/src/main/scala/fj/data/ArbitraryNonEmptyList.scala b/props-core-scalacheck/src/main/scala/fj/data/ArbitraryNonEmptyList.scala
@@ -0,0 +1,16 @@
+package fj.data
+
+import fj.data.NonEmptyList.nel
+import org.scalacheck.Arbitrary.arbitrary
+import org.scalacheck.{Arbitrary, Gen}
+
+/**
+  * A Scalacheck [[Arbitrary]] for [[NonEmptyList]].
+  */
+object ArbitraryNonEmptyList {
+  implicit def arbitraryNonEmptyList[A](implicit a: Arbitrary[A]): Arbitrary[NonEmptyList[A]] =
+    Arbitrary(nelOf(arbitrary[A]))
+
+  def nelOf[A](g: => Gen[A]): Gen[NonEmptyList[A]] =
+    Gen.nonEmptyListOf(g).map(l => l.tail.foldRight(nel(l.head))((x, n) => n.cons(x)))
+}
