fix(NonEmptyList DecodeJson): made error message a little bit better (#1

)

* feat(ArgonautHelpers): added encodeDecodeLaw, so it can be used in
  other projects

  * refactor(scalatest): removed and replaced with scalacheck

argonaut/src/main/scala/com/imageintelligence/galahad/argonaut/ArgonautHelpers.scala

@@ -7,7 +7,7 @@ import argonaut._
 import argonaut.Argonaut._
 import java.util.UUID
 import java.util.concurrent.TimeUnit
-
+import org.scalacheck.{Arbitrary, Prop}
 import scala.concurrent.duration.Duration
 import scalaz._
 import Scalaz._
@@ -51,13 +51,18 @@ object ArgonautHelpers {
   implicit def NonEmptyListDecodeJson[A: DecodeJson]: DecodeJson[NonEmptyList[A]] = {
     implicitly[DecodeJson[List[A]]].flatMap(l =>
       DecodeJson[NonEmptyList[A]](c => std.list.toNel(l) match {
-        case None => DecodeResult.fail("[A]NonEmptyList[A]", c.history)
+        case None => DecodeResult.fail("Could not decode non empty list", c.history)
         case Some(n) => DecodeResult.ok(n)
       })
-    ) setName "[A]NonEmptyList[A]"
+    )
   }
 
   implicit def NonEmptyListEncodeJson[A: EncodeJson]: EncodeJson[NonEmptyList[A]] =
     fromFoldable[NonEmptyList, A]
 
+  def encodeDecodeLaw[A: DecodeJson : EncodeJson : Arbitrary]: Prop = {
+    Prop.forAll { a: A =>
+      CodecJson.codecLaw(CodecJson.derived[A])(a)
+    }
+  }
 }

argonaut/src/test/scala/com/imageintelligence/galahad/argonaut/ArgonautHelpersSpec.scala

@@ -5,35 +5,24 @@ import java.time.Instant
 import java.util.UUID
 
 import argonaut._
-import org.scalacheck._
 import ArgonautHelpers._
 import com.imageintelligence.galahad.core.Generators._
-import org.scalatest.PropSpec
-import org.scalatest.prop.Checkers
+import org.scalacheck._
 
 import scala.concurrent.duration.Duration
+import scalaz.NonEmptyList
+
+class ArgonautHelpersSpec extends Properties("ArgonautHelpers") {
 
-class ArgonautHelpersSpec extends PropSpec with Checkers {
+  property("URL encode/decode") = encodeDecodeLaw[URL]
 
-  def encodeDecodeLaw[A: DecodeJson : EncodeJson : Arbitrary]: Prop = {
-    org.scalacheck.Prop.forAll { a: A =>
-      implicitly[DecodeJson[A]].apply(implicitly[EncodeJson[A]].apply(a).hcursor).value exists (_ === a)
-    }
-  }
+  property("UUID encode/decode") = encodeDecodeLaw[UUID]
 
-  property("URL encode/decode") {
-    check(encodeDecodeLaw[URL], MinSuccessful(100))
-  }
+  property("Duration encode/decode") = encodeDecodeLaw[Duration]
 
-  property("UUID encode/decode") {
-    check(encodeDecodeLaw[UUID], MinSuccessful(100))
-  }
+  property("Instant encode/decode") = encodeDecodeLaw[Instant]
 
-  property("Duration encode/decode") {
-    check(encodeDecodeLaw[Duration], MinSuccessful(100))
-  }
+  property("NonEmptyList[Int] encode/decode") = encodeDecodeLaw[NonEmptyList[Int]]
 
-  property("Instant encode/decode") {
-    check(encodeDecodeLaw[Instant], MinSuccessful(100))
-  }
+  property("NonEmptyList[String] encode/decode") = encodeDecodeLaw[NonEmptyList[String]]
 }

core/src/test/scala/com/imageintelligence/galahad/core/Generators.scala

@@ -8,6 +8,8 @@ import java.util.concurrent.TimeUnit
 import org.scalacheck._
 
 import scala.concurrent.duration.Duration
+import scalaz._
+import Scalaz._
 
 
 object Generators {
@@ -25,6 +27,10 @@ object Generators {
     path     <- Gen.listOfN(length, genPathElement)
   } yield new URL(protocol, host, port, path.mkString("/", "/", ""))
 
+  def genNel[A](g: Gen[A]): Gen[NonEmptyList[A]] = {
+    Gen.nonEmptyListOf(g).map(l => NonEmptyList.nel(l.head, l.tail.toIList))
+  }
+
   val genDuration: Gen[Duration] =
     Arbitrary.arbInt.arbitrary.map(i => Duration.create(i.toLong, TimeUnit.MILLISECONDS))
 
@@ -35,4 +41,6 @@ object Generators {
   implicit val arbDuration: Arbitrary[Duration] = Arbitrary(genDuration)
   implicit val arbUUID: Arbitrary[UUID] = Arbitrary(Gen.uuid)
   implicit val arbInstant: Arbitrary[Instant] = Arbitrary(genInstant)
+  implicit val arbNelInt: Arbitrary[NonEmptyList[Int]] = Arbitrary(genNel(Gen.choose(Int.MinValue, Int.MaxValue)))
+  implicit val arbNelString: Arbitrary[NonEmptyList[String]] = Arbitrary(genNel(Gen.alphaStr))
 }

project/Depend.scala

@@ -11,9 +11,9 @@ object Depend {
   lazy val argonaut = Seq("io.argonaut" %% "argonaut" % argonautVersion)
 
   lazy val scalaTestCheck = Seq(
-    "org.scalatest"   %% "scalatest"                 % "2.2.4",
-    "org.scalacheck"  %% "scalacheck"                % "1.12.1"
-  ).map(_.withSources).map(_ % "test")
+    "org.scalacheck"  %% "scalacheck" % "1.12.5",
+    "org.scalacheck"  %% "scalacheck" % "1.12.5" % "test"
+  ).map(_.withSources)
 
   lazy val depResolvers = Seq(
     "Scalaz Bintray Repo" at "http://dl.bintray.com/scalaz/releases",