TimeSlip: Time manipulation for JVM test cases

TimeSlip allows test cases to manipulate time by providing a concrete java.time.Clock implementation that will operate in a deterministic way, independent of the actual passage of time.

The TimeSlip API is specifically designed to be easy to use from Kotlin and Java code.

Installation

Releases are published to maven central.

It can be included in your project by including the following in your project's build configuration.

dependencies {
    testImplementation 'com.hypercubetools:timeslip:0.1.0'
}

<dependency>
  <groupId>com.hypercubetools</groupId>
  <artifactId>timeslip</artifactId>
  <version>0.1.0</version>
  <type>pom</type>
</dependency>

Detailed Documentation

Find more information about the API and how to use it on the project website

Examples

fun formatTime(clock: Clock) =
    DateTimeFormatter.ISO_TIME.withZone(clock.zone).format(clock.instant())

val constClock = TimeSlip.at(Instant.parse("2007-12-03T10:15:30.00Z"))
println(formatTime(constClock))
println(formatTime(constClock))
println(formatTime(constClock))

// 10:15:30Z
// 10:15:30Z
// 10:15:30Z

val tickingClock = TimeSlip.startAt(Instant.parse("2007-12-03T10:15:30.00Z"))
println(formatTime(tickingClock))
println(formatTime(tickingClock))
println(formatTime(tickingClock))

// 10:15:30Z
// 10:15:31Z
// 10:15:32Z

val ticking2MinClock = TimeSlip.startAt(
    Instant.parse("2007-12-03T10:15:30.00Z"),
    tickAmount = Duration.ofMinutes(2)
)
println(formatTime(ticking2MinClock))
println(formatTime(ticking2MinClock))
println(formatTime(ticking2MinClock))

// 10:15:30Z
// 10:17:30Z
// 10:19:30Z

val sequenceClock = TimeSlip.sequence {
    first(Instant.parse("2007-12-03T10:15:30.00Z"))
    then(Instant.parse("2007-12-03T10:16:00.00Z"), Instant.parse("2007-12-03T10:17:00.00Z"))
}
println(formatTime(sequenceClock))
println(formatTime(sequenceClock))
println(formatTime(sequenceClock))

// 10:15:30Z
// 10:16:00Z
// 10:17:00Z