Universally unique identifiers using standard and JUG APIs / published by https://github.com/dacr/code-examples-manager #df9334be-764b-4e63-a09a-03cb48540fbe/7fff8a4826c21f8b5f8e921372c938fcf652b80d

uuids.sc

// summary : Universally unique identifiers using standard and JUG APIs
// keywords : uuid, named-uuid, jug, @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 : df9334be-764b-4e63-a09a-03cb48540fbe
// created-on : 2021-12-21T16:56:05+01:00
// managed-by : https://github.com/dacr/code-examples-manager
// run-with : scala-cli $file

// ---------------------
//> using scala "3.4.2"
//> using dep "org.scalatest::scalatest:3.2.16"
//> using dep "com.fasterxml.uuid:java-uuid-generator:4.2.0"
//> using dep "org.slf4j:slf4j-nop:2.0.7"
//> using objectWrapper
// ---------------------

import org.scalatest.*, flatspec.*, matchers.*

import java.util.UUID
import com.fasterxml.uuid.Generators

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

  "standard UUID" should "be able to generate random UUID" in {
    val uuid = UUID.randomUUID()
    UUID.fromString(uuid.toString) shouldBe uuid
  }

  "name based UUID generator" should "give always the same uuid when using the same input" in {
    val myInput   = "blah bouh"
    val generator = Generators.nameBasedGenerator()
    val uuid1     = generator.generate(myInput)
    val uuid2     = generator.generate(myInput)
    info("Using the same name source, you always get the same UUID")
    uuid1 shouldBe uuid2
  }

  it should "give distinct uuids if a distinct namespace are used " in {
    val myInput = "blah bouh"

    val namespace1  = UUID.randomUUID()
    val generator1a = Generators.nameBasedGenerator(namespace1)
    val generator1b = Generators.nameBasedGenerator(namespace1)

    val namespace2 = UUID.randomUUID()
    val generator2 = Generators.nameBasedGenerator(namespace2)

    generator1a.generate(myInput) shouldBe generator1a.generate(myInput)
    generator1a.generate(myInput) shouldBe generator1b.generate(myInput)

    generator1a.generate(myInput) should not be generator2.generate(myInput)
  }

  it should "also be possible to generate named base UUID using only the standard JDK" in {
    val myInput = "blah bouh"
    val uuid1   = UUID.nameUUIDFromBytes(myInput.getBytes)
    val uuid2   = UUID.nameUUIDFromBytes(myInput.getBytes)
    info("Using the same name source, you always get the same UUID")
    uuid1 shouldBe uuid2
  }
}

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