AdjustableTickingClock

AdjustableTickingClock.kt

class AdjustableTickingClock(
    private val startTime: Instant = EPOCH,
    private val tick: Duration = Duration.ofSeconds(5)
) : Clock() {
    private var currentTime = startTime
    override fun getZone() = ZoneId.of("UTC")
    override fun withZone(zone: ZoneId?) = this
    override fun instant() = currentTime.also { currentTime += tick }

    fun reset(): AdjustableTickingClock {
        currentTime = startTime
        return this
    }

    fun goBackBy(duration: Duration): AdjustableTickingClock {
        currentTime -= duration
        return this
    }

    fun goForwardBy(duration: Duration): AdjustableTickingClock {
        currentTime += duration
        return this
    }

    fun nowIs(now: Instant) {
        currentTime = now
    }
}