TestClock

TestClock makes it easy to deterministically and efficiently test effects involving the passage of time.

Instead of waiting for actual time to pass, sleep and methods implemented in terms of it schedule effects to take place at a given clock time. Users can adjust the clock time using the adjust and setTime methods, and all effects scheduled to take place on or before that time will automatically be run in order.

For example, here is how we can test ZIO#timeout using TestClock:

import zio.ZIO
import zio.duration._
import zio.test.environment.TestClock

for {
  fiber  <- ZIO.sleep(5.minutes).timeout(1.minute).fork
  _      <- TestClock.adjust(1.minute)
  result <- fiber.join
} yield result == None

Note how we forked the fiber that sleep was invoked on. Calls to sleep and methods derived from it will semantically block until the time is set to on or after the time they are scheduled to run. If we didn't fork the fiber on which we called sleep we would never get to set the time on the line below. Thus, a useful pattern when using TestClock is to fork the effect being tested, then adjust the clock time, and finally verify that the expected effects have been performed.

For example, here is how we can test an effect that recurs with a fixed delay:

import zio.Queue
import zio.duration._
import zio.test.environment.TestClock

for {
  q <- Queue.unbounded[Unit]
  _ <- q.offer(()).delay(60.minutes).forever.fork
  a <- q.poll.map(_.isEmpty)
  _ <- TestClock.adjust(60.minutes)
  b <- q.take.as(true)
  c <- q.poll.map(_.isEmpty)
  _ <- TestClock.adjust(60.minutes)
  d <- q.take.as(true)
  e <- q.poll.map(_.isEmpty)
} yield a && b && c && d && e

Here we verify that no effect is performed before the recurrence period, that an effect is performed after the recurrence period, and that the effect is performed exactly once. The key thing to note here is that after each recurrence the next recurrence is scheduled to occur at the appropriate time in the future, so when we adjust the clock by 60 minutes exactly one value is placed in the queue, and when we adjust the clock by another 60 minutes exactly one more value is placed in the queue.

Linear Supertypes

Serializable, Serializable, AnyRef, Any

Type Members

final case class Data(duration: Duration, sleeps: List[(Duration, Promise[Nothing, Unit])], timeZone: ZoneId) extends Product with Serializable

Data represents the state of the TestClock, incuding the clock time and time zone.
trait Service extends Restorable
final case class Sleep(duration: Duration, promise: Promise[Nothing, Unit], fiberId: Id) extends Product with Serializable

Sleep represents the state of a scheduled effect, including the time the effect is scheduled to run, a promise that can be completed to resume execution of the effect, and the fiber executing the effect.
final case class Test(clockState: Ref[Data], live: Live.Service, warningState: RefM[WarningData]) extends clock.Clock.Service with Service with Product with Serializable
sealed trait WarningData extends AnyRef

WarningData describes the state of the warning message that is displayed if a test is using time by is not advancing the TestClock.
WarningData describes the state of the warning message that is displayed if a test is using time by is not advancing the TestClock. The possible states are Start if a test has not used time, Pending if a test has used time but has not adjusted the TestClock, and Done if a test has adjusted the TestClock or the warning message has already been displayed.

Value Members

final def !=(arg0: Any): Boolean

Definition Classes
AnyRef → Any
final def ##(): Int

Definition Classes
AnyRef → Any
final def ==(arg0: Any): Boolean

Definition Classes
AnyRef → Any
object WarningData
def adjust(duration: ⇒ Duration): ZIO[TestClock, Nothing, Unit]

Accesses a TestClock instance in the environment and increments the time by the specified duration, running any actions scheduled for on or before the new time in order.
val any: ZLayer[Clock with TestClock, Nothing, Clock with TestClock]
final def asInstanceOf[T0]: T0

Definition Classes
Any
def clone(): AnyRef

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( ... )
val default: ZLayer[Live, Nothing, Clock with TestClock]
final def eq(arg0: AnyRef): Boolean

Definition Classes
AnyRef
def equals(arg0: Any): Boolean

Definition Classes
AnyRef → Any
def finalize(): Unit

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( classOf[java.lang.Throwable] )
final def getClass(): Class[_]

Definition Classes
AnyRef → Any
def hashCode(): Int

Definition Classes
AnyRef → Any
final def isInstanceOf[T0]: Boolean

Definition Classes
Any
def live(data: Data): ZLayer[Live, Nothing, Clock with TestClock]

Constructs a new Test object that implements the TestClock interface.
Constructs a new Test object that implements the TestClock interface. This can be useful for mixing in with implementations of other interfaces.
final def ne(arg0: AnyRef): Boolean

Definition Classes
AnyRef
final def notify(): Unit

Definition Classes
AnyRef
final def notifyAll(): Unit

Definition Classes
AnyRef
val save: ZIO[TestClock, Nothing, UIO[Unit]]

Accesses a TestClock instance in the environment and saves the clock state in an effect which, when run, will restore the TestClock to the saved state.
def setDateTime(dateTime: ⇒ OffsetDateTime): ZIO[TestClock, Nothing, Unit]

Accesses a TestClock instance in the environment and sets the clock time to the specified OffsetDateTime, running any actions scheduled for on or before the new time in order.
def setTime(duration: ⇒ Duration): ZIO[TestClock, Nothing, Unit]

Accesses a TestClock instance in the environment and sets the clock time to the specified time in terms of duration since the epoch, running any actions scheduled for on or before the new time in order.
def setTimeZone(zone: ⇒ ZoneId): ZIO[TestClock, Nothing, Unit]

Accesses a TestClock instance in the environment, setting the time zone to the specified time zone.
Accesses a TestClock instance in the environment, setting the time zone to the specified time zone. The clock time in terms of nanoseconds since the epoch will not be altered and no scheduled actions will be run as a result of this effect.
val sleeps: ZIO[TestClock, Nothing, List[Duration]]

Accesses a TestClock instance in the environment and returns a list of times that effects are scheduled to run.
final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
AnyRef
val timeZone: ZIO[TestClock, Nothing, ZoneId]

Accesses a TestClock instance in the environment and returns the current time zone.
def toString(): String

Definition Classes
AnyRef → Any
final def wait(): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long, arg1: Int): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )

Related Doc: package environment

object TestClock extends Serializable

Type Members

final case class Data(duration: Duration, sleeps: List[(Duration, Promise[Nothing, Unit])], timeZone: ZoneId) extends Product with Serializable

trait Service extends Restorable

final case class Sleep(duration: Duration, promise: Promise[Nothing, Unit], fiberId: Id) extends Product with Serializable

final case class Test(clockState: Ref[Data], live: Live.Service, warningState: RefM[WarningData]) extends clock.Clock.Service with Service with Product with Serializable

sealed trait WarningData extends AnyRef

Value Members

final def !=(arg0: Any): Boolean

final def ##(): Int

final def ==(arg0: Any): Boolean

object WarningData

def adjust(duration: ⇒ Duration): ZIO[TestClock, Nothing, Unit]

val any: ZLayer[Clock with TestClock, Nothing, Clock with TestClock]

final def asInstanceOf[T0]: T0

def clone(): AnyRef

val default: ZLayer[Live, Nothing, Clock with TestClock]

final def eq(arg0: AnyRef): Boolean

def equals(arg0: Any): Boolean

def finalize(): Unit

final def getClass(): Class[_]

def hashCode(): Int

final def isInstanceOf[T0]: Boolean

def live(data: Data): ZLayer[Live, Nothing, Clock with TestClock]

final def ne(arg0: AnyRef): Boolean

final def notify(): Unit

final def notifyAll(): Unit

val save: ZIO[TestClock, Nothing, UIO[Unit]]

def setDateTime(dateTime: ⇒ OffsetDateTime): ZIO[TestClock, Nothing, Unit]

def setTime(duration: ⇒ Duration): ZIO[TestClock, Nothing, Unit]

def setTimeZone(zone: ⇒ ZoneId): ZIO[TestClock, Nothing, Unit]

val sleeps: ZIO[TestClock, Nothing, List[Duration]]

final def synchronized[T0](arg0: ⇒ T0): T0

val timeZone: ZIO[TestClock, Nothing, ZoneId]

def toString(): String

final def wait(): Unit

final def wait(arg0: Long, arg1: Int): Unit

final def wait(arg0: Long): Unit

Inherited from Serializable

Inherited from Serializable

Inherited from AnyRef

Inherited from Any

Ungrouped