clockwork

A simple fake clock for Go.

Usage

Replace uses of the time package with the clockwork.Clock interface instead.

For example, instead of using time.Sleep directly:

funcmyFunc() {
time.Sleep(3*time.Second)
doSomething()
}

Inject a clock and use its Sleep method instead:

funcmyFunc(clock clockwork.Clock) {
clock.Sleep(3*time.Second)
doSomething()
}

Now you can easily test myFunc with a FakeClock:

funcTestMyFunc(t*testing.T) {
ctx:=context.Background()
c:=clockwork.NewFakeClock()
// Start our sleepy functionvarwg sync.WaitGroupwg.Add(1)
gofunc() {
myFunc(c)
wg.Done()
}()
// Ensure we wait until myFunc is waiting on the clock.// Use a context to avoid blocking forever if something// goes wrong.ctx, cancel:=context.WithTimeout(ctx, 10*time.Second)
defercancel()
c.BlockUntilContext(ctx, 1)
assertState()
// Advance the FakeClock forward in timec.Advance(3*time.Second)
// Wait until the function completeswg.Wait()
assertState()
}

and in production builds, simply inject the real clock instead:

myFunc(clockwork.NewRealClock())

See example_test.go for a full example.

Credits

clockwork is inspired by @wickman's threaded fake clock, and the Golang playground

License

Apache License, Version 2.0. Please see License File for more information.