clockwork

README

clockwork

a simple fake clock for golang

Usage

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

For example, instead of using time.Sleep directly:

func my_func() {
	time.Sleep(3 * time.Second)
	do_something()
}

inject a clock and use its Sleep method instead:

func my_func(clock clockwork.Clock) {
	clock.Sleep(3 * time.Second)
	do_something()
}

Now you can easily test my_func with a FakeClock:

func TestMyFunc(t *testing.T) {
	c := clockwork.NewFakeClock()

	// Start our sleepy function
	my_func(c)

	// Ensure we wait until my_func is sleeping
	c.BlockUntil(1)

	assert_state()

	// Advance the FakeClock forward in time
	c.Advance(3)

	assert_state()
}

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

my_func(clockwork.NewRealClock())

See example_test.go for a full example.

Credits

Inspired by @wickman's threaded fake clock, and the [Golang playground](http://blog.golang.org/playground#Faking time)

Documentation

Index

• type Clock
  • func NewRealClock() Clock
• type FakeClock
  • func NewFakeClock() FakeClock

Types

type Clock

type Clock interface {
	After(d time.Duration) <-chan time.Time
	Sleep(d time.Duration)
	Now() time.Time
}

Clock provides an interface that packages can use instead of directly using the time module, so that chronology-related behavior can be tested

func NewRealClock

func NewRealClock() Clock

NewRealClock returns a Clock which simply delegates calls to the actual time package; it should be used by packages in production.

type FakeClock

type FakeClock interface {
	Clock
	// Advance advances the FakeClock to a new point in time, ensuring any existing
	// sleepers are notified appropriately before returning
	Advance(d time.Duration)
	// BlockUntil will block until the FakeClock has the given number of
	// sleepers (callers of Sleep or After)
	BlockUntil(n int)
}

FakeClock provides an interface for a clock which can be manually advanced through time

func NewFakeClock

func NewFakeClock() FakeClock

NewFakeClock returns a FakeClock implementation which can be manually advanced through time for testing.