mclock

Documentation

Overview

Package mclock is a wrapper for a monotonic clock source

Index

• type AbsTime
  • func Now() AbsTime
  • func (t AbsTime) Add(d time.Duration) AbsTime
• type Clock
• type Simulated
  • func (s *Simulated) ActiveTimers() int
  • func (s *Simulated) After(d time.Duration) <-chan time.Time
  • func (s *Simulated) AfterFunc(d time.Duration, fn func()) Timer
  • func (s *Simulated) Now() AbsTime
  • func (s *Simulated) Run(d time.Duration)
  • func (s *Simulated) Sleep(d time.Duration)
  • func (s *Simulated) WaitForTimers(n int)
• type System
  • func (System) After(d time.Duration) <-chan time.Time
  • func (System) AfterFunc(d time.Duration, f func()) Timer
  • func (System) Now() AbsTime
  • func (System) Sleep(d time.Duration)
• type Timer

Types

type AbsTime

type AbsTime time.Duration

AbsTime represents absolute monotonic time.

func Now

func Now() AbsTime

Now returns the current absolute monotonic time.

func (AbsTime) Add

func (t AbsTime) Add(d time.Duration) AbsTime

Add returns t + d.

type Clock

type Clock interface {
	Now() AbsTime
	Sleep(time.Duration)
	After(time.Duration) <-chan time.Time
	AfterFunc(d time.Duration, f func()) Timer
}

The Clock interface makes it possible to replace the monotonic system clock with a simulated clock.

type Simulated

type Simulated struct {
	// contains filtered or unexported fields
}

Simulated implements a virtual Clock for reproducible time-sensitive tests. It simulates a scheduler on a virtual timescale where actual processing takes zero time.

The virtual clock doesn't advance on its own, call Run to advance it and execute timers. Since there is no way to influence the Go scheduler, testing timeout behaviour involving goroutines needs special care. A good way to test such timeouts is as follows: First perform the action that is supposed to time out. Ensure that the timer you want to test is created. Then run the clock until after the timeout. Finally observe the effect of the timeout using a channel or semaphore.

func (*Simulated) ActiveTimers

func (s *Simulated) ActiveTimers() int

ActiveTimers returns the number of timers that haven't fired.

func (*Simulated) After

func (s *Simulated) After(d time.Duration) <-chan time.Time

After returns a channel which receives the current time after the clock has advanced by d.

func (*Simulated) AfterFunc

func (s *Simulated) AfterFunc(d time.Duration, fn func()) Timer

AfterFunc runs fn after the clock has advanced by d. Unlike with the system clock, fn runs on the goroutine that calls Run.

func (*Simulated) Now

func (s *Simulated) Now() AbsTime

Now returns the current virtual time.

func (*Simulated) Run

func (s *Simulated) Run(d time.Duration)

Run moves the clock by the given duration, executing all timers before that duration.

func (*Simulated) Sleep

func (s *Simulated) Sleep(d time.Duration)

Sleep blocks until the clock has advanced by d.

func (*Simulated) WaitForTimers

func (s *Simulated) WaitForTimers(n int)

WaitForTimers waits until the clock has at least n scheduled timers.

type System

type System struct{}

System implements Clock using the system clock.

func (System) After

func (System) After(d time.Duration) <-chan time.Time

After returns a channel which receives the current time after d has elapsed.

func (System) AfterFunc

func (System) AfterFunc(d time.Duration, f func()) Timer

AfterFunc runs f on a new goroutine after the duration has elapsed.

func (System) Now

func (System) Now() AbsTime

Now returns the current monotonic time.

func (System) Sleep

func (System) Sleep(d time.Duration)

Sleep blocks for the given duration.

type Timer

type Timer interface {
	Stop() bool
}

Timer represents a cancellable event returned by AfterFunc