upickle scala json API cookbook as unit test cases. / published by https://github.com/dacr/code-examples-manager #27899ec3-598b-4734-a4ec-98cd27b29276/bd4eb581a25116cdfa6f3db6f93115cbc6213366

json-upickle.sc

// summary : upickle scala json API cookbook as unit test cases.
// keywords : scala, scalatest, upickle, json, @testable
// publish : gist
// authors : David Crosson
// license : Apache NON-AI License Version 2.0 (https://raw.githubusercontent.com/non-ai-licenses/non-ai-licenses/main/NON-AI-APACHE2)
// id : 27899ec3-598b-4734-a4ec-98cd27b29276
// created-on : 2019-09-27T21:04:36Z
// managed-by : https://github.com/dacr/code-examples-manager
// run-with : scala-cli $file

// ---------------------
//> using scala "3.6.4"
//> using dep "org.scalatest::scalatest:3.2.19"
//> using dep "com.lihaoyi::upickle:4.1.0"
//> using objectWrapper
// ---------------------

object OptionPickler extends upickle.AttributeTagged {
  override implicit def OptionWriter[T: Writer]: Writer[Option[T]] =
    implicitly[Writer[T]].comap[Option[T]] {
      case None    => null.asInstanceOf[T]
      case Some(x) => x
    }

  override implicit def OptionReader[T: Reader]: Reader[Option[T]] = {
    new Reader.Delegate[Any, Option[T]](implicitly[Reader[T]].map(Some(_))) {
      override def visitNull(index: Int) = None
    }
  }
}

import upickle.default.ReadWriter

import org.scalatest.*, matchers.*

case class Person(age: Int, name: String)

case class Person2(age: Int, name: String) derives ReadWriter

case class Person3(age: Int, name: String, gender: Option[String]=Some("male")) derives ReadWriter

case class Person4(age: Int, name: String, gender: Option[String]) derives OptionPickler.ReadWriter

class JsonUpickleCookBook extends flatspec.AnyFlatSpec with should.Matchers {
  override def suiteName = "JsonUpickleCookBook"

  "upickle" should "deserialize json array strings" in {
    val decoded = upickle.default.read[Array[Int]]("""[1,2,3]""")
    decoded shouldBe Array(1, 2, 3)
  }

  it should "deserialize scala case classes ?" in {
    val decoded = upickle.default.read[Person2]("""{"age":42, "name":"john"}""")
    decoded shouldBe Person2(42, "john")
  }

  it should "deserialize scala case classes with optional field? default value is supported" in {
    val decoded = upickle.default.read[Person3]("""{"age":42, "name":"john"} """)
    decoded shouldBe Person3(42, "john", Some("male"))
  }

  it should "deserialize scala case classes with optional field? " in {
    val decoded = OptionPickler.read[Person4]("""{"age":42, "name":"john", "gender":"male"}""")
    decoded shouldBe Person4(42, "john", Some("male"))
  }

  it should "deserialize scala list" in {
    val decoded = upickle.default.read[List[Int]]("""[1,2,3]""")
    decoded shouldBe List(1, 2, 3)
  }

  it should "provide an AST" in {
    import ujson.*
    val json = Obj(
      "age"    -> Num(42),
      "name"   -> Str("john"),
      "gender" -> Arr("truc", "bidule")
    )
    upickle.default.write(json) shouldBe """{"age":42,"name":"john","gender":["truc","bidule"]}"""
  }

//  it should "be able to jsonify map data structure" in {
//    val jwtId           = java.util.UUID.randomUUID().toString
//    val nowEpochSeconds = java.time.Instant.now.getEpochSecond()
//
//    val result =
//      s"""{
//         |  "jti" : "$jwtId",
//         |  "iss" : "this-app",
//         |  "iat" : $nowEpochSeconds,
//         |  "exp" : ${nowEpochSeconds + 60L},
//         |  "nbf" : ${nowEpochSeconds + 2L},
//         |  "sub" : "userlogin@example.com"
//         |  "user" : 1
//         |}""".stripMargin
//
//    val claim = Map(
//      "jti"  -> jwtId,                   // JTW ID
//      "iss"  -> "this-app",              // Issuer
//      "iat"  -> nowEpochSeconds,         // Issued at
//      "exp"  -> (nowEpochSeconds + 60L), // Expiration time
//      "nbf"  -> (nowEpochSeconds + 2L),  // Not before
//      "sub"  -> "userlogin@example.com", // The subject
//      "user" -> 1
//    )
//    upickle.default.write(claim)
//  }

}

org.scalatest.tools.Runner.main(Array("-oDF", "-s", classOf[JsonUpickleCookBook].getName))