README
¶
clock
Clock is a small library for mocking time in Go. It provides an interface around the standard library's time package so that the application can use the realtime clock while tests can use the mock clock. This is a maintained fork of benbjohnson's clock package.
Usage
Realtime Clock
Your application can maintain a Clock variable that will allow realtime and mock clocks to be interchangeable. For example, if you had an Application type:
import "github.com/filecoin-project/go-clock"
type Application struct {
Clock clock.Clock
}
You could initialize it to use the realtime clock like this:
var app Application
app.Clock = clock.New()
...
Then all timers and time-related functionality should be performed from the Clock variable.
Mocking time
In your tests, you will want to use a Mock clock:
import (
"testing"
"github.com/filecoin-project/go-clock"
)
func TestApplication_DoSomething(t *testing.T) {
mock := clock.NewMock()
app := Application{Clock: mock}
...
}
Now that you've initialized your application to use the mock clock, you can adjust the time programmatically. The mock clock always starts from the Unix epoch (midnight UTC on Jan 1, 1970).
Controlling time
The mock clock provides the same functions that the standard library's time package provides. For example, to find the current time, you use the Now() function:
mock := clock.NewMock()
// Find the current time.
mock.Now().UTC() // 1970-01-01 00:00:00 +0000 UTC
// Move the clock forward.
mock.Add(2 * time.Hour)
// Check the time again. It's 2 hours later!
mock.Now().UTC() // 1970-01-01 02:00:00 +0000 UTC
Timers and Tickers are also controlled by this same mock clock. They will only execute when the clock is moved forward:
mock := clock.NewMock()
count := 0
// Kick off a timer to increment every 1 mock second.
go func() {
ticker := mock.Ticker(1 * time.Second)
for {
<-ticker.C
count++
}
}()
runtime.Gosched()
// Move the clock forward 10 seconds.
mock.Add(10 * time.Second)
// This prints 10.
fmt.Println(count)
Documentation
¶
Index ¶
- type Clock
- type Duration
- type Mock
- func (m *Mock) Add(d time.Duration)
- func (m *Mock) After(d time.Duration) <-chan time.Time
- func (m *Mock) AfterFunc(d time.Duration, f func()) *Timer
- func (m *Mock) Now() time.Time
- func (m *Mock) Set(t time.Time)
- func (m *Mock) Since(t time.Time) time.Duration
- func (m *Mock) Sleep(d time.Duration)
- func (m *Mock) Tick(d time.Duration) <-chan time.Time
- func (m *Mock) Ticker(d time.Duration) *Ticker
- func (m *Mock) Timer(d time.Duration) *Timer
- func (m *Mock) Until(t time.Time) time.Duration
- func (m *Mock) WaitForAllTimers() time.Time
- func (m *Mock) WithDeadline(parent context.Context, deadline time.Time) (context.Context, context.CancelFunc)
- func (m *Mock) WithTimeout(parent context.Context, timeout time.Duration) (context.Context, context.CancelFunc)
- type Ticker
- type Timer
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Clock ¶
type Clock interface {
After(d time.Duration) <-chan time.Time
AfterFunc(d time.Duration, f func()) *Timer
Now() time.Time
Since(t time.Time) time.Duration
Until(t time.Time) time.Duration
Sleep(d time.Duration)
Tick(d time.Duration) <-chan time.Time
Ticker(d time.Duration) *Ticker
Timer(d time.Duration) *Timer
WithDeadline(parent context.Context, d time.Time) (context.Context, context.CancelFunc)
WithTimeout(parent context.Context, t time.Duration) (context.Context, context.CancelFunc)
}
Clock represents an interface to the functions in the standard library time package. Two implementations are available in the clock package. The first is a real-time clock which simply wraps the time package's functions. The second is a mock clock which will only change when programmatically adjusted.
type Mock ¶
type Mock struct {
// contains filtered or unexported fields
}
Mock represents a mock clock that only moves forward programmically. It can be preferable to a real-time clock when testing time-based functionality.
func NewMock ¶
func NewMock() *Mock
NewMock returns an instance of a mock clock. The current time of the mock clock on initialization is the Unix epoch.
func (*Mock) Add ¶
Add moves the current time of the mock clock forward by the specified duration. This should only be called from a single goroutine at a time.
func (*Mock) After ¶
After waits for the duration to elapse and then sends the current time on the returned channel.
Example ¶
// Create a new mock clock.
clock := NewMock()
var count counter
ready := make(chan struct{})
// Create a channel to execute after 10 mock seconds.
go func() {
ch := clock.After(10 * time.Second)
close(ready)
<-ch
count.incr()
}()
<-ready
// Print the starting value.
fmt.Printf("%s: %d\n", clock.Now().UTC(), count.get())
// Move the clock forward 5 seconds and print the value again.
clock.Add(5 * time.Second)
fmt.Printf("%s: %d\n", clock.Now().UTC(), count.get())
// Move the clock forward 5 seconds to the tick time and check the value.
clock.Add(5 * time.Second)
fmt.Printf("%s: %d\n", clock.Now().UTC(), count.get())
Output: 1970-01-01 00:00:00 +0000 UTC: 0 1970-01-01 00:00:05 +0000 UTC: 0 1970-01-01 00:00:10 +0000 UTC: 1
func (*Mock) AfterFunc ¶
AfterFunc waits for the duration to elapse and then executes a function in its own goroutine. A Timer is returned that can be stopped.
Example ¶
// Create a new mock clock.
clock := NewMock()
var count counter
count.incr()
// Execute a function after 10 mock seconds.
clock.AfterFunc(10*time.Second, func() {
count.incr()
})
gosched()
// Print the starting value.
fmt.Printf("%s: %d\n", clock.Now().UTC(), count.get())
// Move the clock forward 10 seconds and print the new value.
clock.Add(10 * time.Second)
fmt.Printf("%s: %d\n", clock.Now().UTC(), count.get())
Output: 1970-01-01 00:00:00 +0000 UTC: 1 1970-01-01 00:00:10 +0000 UTC: 2
func (*Mock) Set ¶
Set sets the current time of the mock clock to a specific one. This should only be called from a single goroutine at a time.
func (*Mock) Sleep ¶
Sleep pauses the goroutine for the given duration on the mock clock. The clock must be moved forward in a separate goroutine.
Example ¶
// Create a new mock clock.
clock := NewMock()
var count counter
// Execute a function after 10 mock seconds.
go func() {
clock.Sleep(10 * time.Second)
count.incr()
}()
gosched()
// Print the starting value.
fmt.Printf("%s: %d\n", clock.Now().UTC(), count.get())
// Move the clock forward 10 seconds and print the new value.
clock.Add(10 * time.Second)
fmt.Printf("%s: %d\n", clock.Now().UTC(), count.get())
Output: 1970-01-01 00:00:00 +0000 UTC: 0 1970-01-01 00:00:10 +0000 UTC: 1
func (*Mock) Tick ¶
Tick is a convenience function for Ticker(). It will return a ticker channel that cannot be stopped.
func (*Mock) Ticker ¶
Ticker creates a new instance of Ticker.
Example ¶
// Create a new mock clock.
clock := NewMock()
var count counter
ready := make(chan struct{})
// Increment count every mock second.
go func() {
ticker := clock.Ticker(1 * time.Second)
close(ready)
for {
<-ticker.C
count.incr()
}
}()
<-ready
// Move the clock forward 10 seconds and print the new value.
clock.Add(10 * time.Second)
fmt.Printf("Count is %d after 10 seconds\n", count.get())
// Move the clock forward 5 more seconds and print the new value.
clock.Add(5 * time.Second)
fmt.Printf("Count is %d after 15 seconds\n", count.get())
Output: Count is 10 after 10 seconds Count is 15 after 15 seconds
func (*Mock) Timer ¶
Timer creates a new instance of Timer.
Example ¶
// Create a new mock clock.
clock := NewMock()
var count counter
ready := make(chan struct{})
// Increment count after a mock second.
go func() {
timer := clock.Timer(1 * time.Second)
close(ready)
<-timer.C
count.incr()
}()
<-ready
// Move the clock forward 10 seconds and print the new value.
clock.Add(10 * time.Second)
fmt.Printf("Count is %d after 10 seconds\n", count.get())
Output: Count is 1 after 10 seconds
func (*Mock) WaitForAllTimers ¶
WaitForAllTimers sets the clock until all timers are expired
func (*Mock) WithDeadline ¶
type Ticker ¶
Ticker holds a channel that receives "ticks" at regular intervals.
Source Files