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zio-test
There is a newer version: 2.1.14
package zio.test

import zio._
import zio.internal.stacktracer.Tracer
import zio.stacktracer.TracingImplicits.disableAutoTrace

/**
 * The `Live` trait provides access to the "live" default ZIO services from
 * within ZIO Test for workflows such as printing test results to the console or
 * timing out tests where it is necessary to access the real implementations of
 * these services.
 *
 * The easiest way to access the "live" services is to use the `live` method
 * with a workflow that would otherwise use the test version of the default ZIO
 * services.
 *
 * {{{
 * import zio.Clock
 * import zio.test._
 *
 * val realTime = live(Clock.nanoTime)
 * }}}
 *
 * The `withLive` method can be used to apply a transformation to a workflow
 * with the live services while ensuring that the workflow itself still runs
 * with the test services, for example to time out a test. Both of these methods
 * are re-exported in the ZIO Test package object for easy availability.
 */
trait Live {
  def provide[R, E, A](zio: ZIO[R, E, A])(implicit trace: Trace): ZIO[R, E, A]
}

object Live {

  val tag: Tag[Live] = Tag[Live]

  final case class Test(zenv: ZEnvironment[Clock with Console with System with Random]) extends Live {
    def provide[R, E, A](zio: ZIO[R, E, A])(implicit trace: Trace): ZIO[R, E, A] =
      DefaultServices.currentServices.locallyWith(_.unionAll(zenv))(zio)
  }

  /**
   * Constructs a new `Live` service that implements the `Live` interface. This
   * typically should not be necessary as the `TestEnvironment` already includes
   * the `Live` service but could be useful if you are mixing in interfaces to
   * create your own environment type.
   */
  val default: ZLayer[Clock with Console with System with Random, Nothing, Live] = {
    implicit val trace = Tracer.newTrace
    ZLayer.scoped {
      for {
        zenv <- ZIO.environment[Clock with Console with System with Random]
        live  = Test(zenv)
        _    <- withLiveScoped(live)
      } yield live
    }
  }

  /**
   * Provides a workflow with the "live" default ZIO services.
   */
  def live[R, E, A](zio: ZIO[R, E, A])(implicit trace: Trace): ZIO[R, E, A] =
    liveWith(_.provide(zio))

  /**
   * Runs a transformation function with the live default ZIO services while
   * ensuring that the workflow itself is run with the test services.
   */
  def withLive[R, E, E1, A, B](
    zio: ZIO[R, E, A]
  )(f: ZIO[R, E, A] => ZIO[R, E1, B])(implicit trace: Trace): ZIO[R, E1, B] =
    DefaultServices.currentServices.getWith(services => live(f(DefaultServices.currentServices.locally(services)(zio))))
}