object TestClock extends Serializable
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.
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Type Members
- final case class Data(duration: Duration, sleeps: List[(Duration, Promise[Nothing, Unit])], timeZone: ZoneId) extends Product with Serializable
Datarepresents the state of theTestClock, including 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
Sleeprepresents 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, annotations: Annotations.Service, warningState: RefM[WarningData]) extends clock.Clock.Service with Service with Product with Serializable
- sealed abstract class WarningData extends AnyRef
WarningDatadescribes the state of the warning message that is displayed if a test is using time by is not advancing theTestClock.WarningDatadescribes the state of the warning message that is displayed if a test is using time by is not advancing theTestClock. The possible states areStartif a test has not used time,Pendingif a test has used time but has not adjusted theTestClock, andDoneif a test has adjusted theTestClockor the warning message has already been displayed.
Value Members
- final def !=(arg0: Any): Boolean
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- final def ##: Int
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- final def ==(arg0: Any): Boolean
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- def adjust(duration: => Duration): URIO[TestClock, Unit]
Accesses a
TestClockinstance 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
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- @throws(classOf[java.lang.CloneNotSupportedException]) @native()
- val default: ZLayer[Live with Annotations, Nothing, Clock with TestClock]
- final def eq(arg0: AnyRef): Boolean
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- def equals(arg0: AnyRef): Boolean
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- def finalize(): Unit
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- def hashCode(): Int
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- final def isInstanceOf[T0]: Boolean
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- def live(data: Data): ZLayer[Live with Annotations, Nothing, Clock with TestClock]
Constructs a new
Testobject that implements theTestClockinterface.Constructs a new
Testobject that implements theTestClockinterface. This can be useful for mixing in with implementations of other interfaces. - final def ne(arg0: AnyRef): Boolean
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- final def notify(): Unit
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- @native()
- final def notifyAll(): Unit
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- val save: ZIO[TestClock, Nothing, UIO[Unit]]
Accesses a
TestClockinstance in the environment and saves the clock state in an effect which, when run, will restore theTestClockto the saved state. - def setDateTime(dateTime: => OffsetDateTime): URIO[TestClock, Unit]
Accesses a
TestClockinstance in the environment and sets the clock time to the specifiedOffsetDateTime, running any actions scheduled for on or before the new time in order. - def setTime(duration: => Duration): URIO[TestClock, Unit]
Accesses a
TestClockinstance 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): URIO[TestClock, Unit]
Accesses a
TestClockinstance in the environment, setting the time zone to the specified time zone.Accesses a
TestClockinstance 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
TestClockinstance in the environment and returns a list of times that effects are scheduled to run. - final def synchronized[T0](arg0: => T0): T0
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- val timeZone: URIO[TestClock, ZoneId]
Accesses a
TestClockinstance in the environment and returns the current time zone. - def toString(): String
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- final def wait(): Unit
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- @throws(classOf[java.lang.InterruptedException])
- final def wait(arg0: Long, arg1: Int): Unit
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- @throws(classOf[java.lang.InterruptedException])
- final def wait(arg0: Long): Unit
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- object WarningData