argonaut sum types

argonaut.scala

import com.vimpelcom.ep.common.Msisdn
import org.scalatest.FunSpecLike
import org.scalatest.Matchers
import argonaut._
import Argonaut._

sealed trait ChallengeProof2FAOutcome

case class ChallengeProof2FAFailure(status: String, meta: String) extends ChallengeProof2FAOutcome

case class ChallengeProof2FASuccess(msisdn: Msisdn) extends ChallengeProof2FAOutcome

object ChallengeProof2FAOutcome {
  implicit val ChallengeProof2FAFailureCodec: CodecJson[ChallengeProof2FAFailure] =
    casecodec2(ChallengeProof2FAFailure.apply, ChallengeProof2FAFailure.unapply)("status", "meta")
  implicit val ChallengeProof2FASuccessCodec =
    casecodec1(ChallengeProof2FASuccess.apply, ChallengeProof2FASuccess.unapply)("msisdn")

  val failureDecoder: DecodeJson[ChallengeProof2FAFailure] = ChallengeProof2FAFailureCodec.Decoder
  val successDecoder: DecodeJson[ChallengeProof2FASuccess] = ChallengeProof2FASuccessCodec.Decoder

  implicit val ChallengeProof2FAOutcomeCodec: CodecJson[ChallengeProof2FAOutcome] =
    CodecJson[ChallengeProof2FAOutcome](
      {
        case out: ChallengeProof2FAFailure => ChallengeProof2FAFailureCodec(out)
        case out: ChallengeProof2FASuccess => ChallengeProof2FASuccessCodec(out)
      },
      c =>
        failureDecoder(c).map(x => x: ChallengeProof2FAOutcome) |||
          successDecoder(c).map(x => x: ChallengeProof2FAOutcome)
    )
}

class FakeSpec extends FunSpecLike with Matchers {
  describe("Json parsing") {
    it("should work") {

      import ChallengeProof2FAOutcome.ChallengeProof2FAOutcomeCodec

      val a: ChallengeProof2FAOutcome = ChallengeProof2FAFailure("status info", "meta info")
      val b: ChallengeProof2FAOutcome = ChallengeProof2FASuccess("msisdn info")

      val aJsonString = """{"status":"status info","meta":"meta info"}"""
      val bJsonString = """{"msisdn":"msisdn info"}"""

      a.asJson.toString shouldEqual aJsonString
      b.asJson.toString shouldEqual bJsonString
      Parse.decodeOption[ChallengeProof2FAOutcome](aJsonString).get shouldEqual ChallengeProof2FAFailure(
        "status info",
        "meta info"
      )
      Parse.decodeOption[ChallengeProof2FAOutcome](bJsonString).get shouldEqual ChallengeProof2FASuccess("msisdn info")
    }
  }
}