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package clock
import (
"context"
"sync"
"sync/atomic"
"testing"
"time"
"github.com/stretchr/testify/require"
)
func TestNowReturnsCurrentTime(t *testing.T) {
now := time.UnixMilli(23829382)
clock := NewDeterministicClock(now)
require.Equal(t, now, clock.Now())
}
func TestAdvanceTime(t *testing.T) {
start := time.UnixMilli(1000)
clock := NewDeterministicClock(start)
clock.AdvanceTime(500 * time.Millisecond)
require.Equal(t, start.Add(500*time.Millisecond), clock.Now())
}
func TestAfter(t *testing.T) {
t.Run("ZeroCompletesImmediately", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
ch := clock.After(0)
require.Len(t, ch, 1, "duration should already have been reached")
})
t.Run("CompletesWhenTimeAdvances", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
ch := clock.After(500 * time.Millisecond)
require.Len(t, ch, 0, "should not complete immediately")
clock.AdvanceTime(499 * time.Millisecond)
require.Len(t, ch, 0, "should not complete before time is due")
clock.AdvanceTime(1 * time.Millisecond)
require.Len(t, ch, 1, "should complete when time is reached")
require.Equal(t, clock.Now(), <-ch)
})
t.Run("CompletesWhenTimeAdvancesPastDue", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
ch := clock.After(500 * time.Millisecond)
require.Len(t, ch, 0, "should not complete immediately")
clock.AdvanceTime(9000 * time.Millisecond)
require.Len(t, ch, 1, "should complete when time is past")
require.Equal(t, clock.Now(), <-ch)
})
t.Run("RegisterAsPending", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
_ = clock.After(500 * time.Millisecond)
ctx, cancelFunc := context.WithTimeout(context.Background(), 10*time.Second)
defer cancelFunc()
require.True(t, clock.WaitForNewPendingTask(ctx), "should have added a new pending task")
})
}
func TestAfterFunc(t *testing.T) {
t.Run("ZeroExecutesImmediately", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
ran := new(atomic.Bool)
timer := clock.AfterFunc(0, func() { ran.Store(true) })
require.True(t, ran.Load(), "duration should already have been reached")
require.False(t, timer.Stop(), "Stop should return false after executing")
})
t.Run("CompletesWhenTimeAdvances", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
ran := new(atomic.Bool)
timer := clock.AfterFunc(500*time.Millisecond, func() { ran.Store(true) })
require.False(t, ran.Load(), "should not complete immediately")
clock.AdvanceTime(499 * time.Millisecond)
require.False(t, ran.Load(), "should not complete before time is due")
clock.AdvanceTime(1 * time.Millisecond)
require.True(t, ran.Load(), "should complete when time is reached")
require.False(t, timer.Stop(), "Stop should return false after executing")
})
t.Run("CompletesWhenTimeAdvancesPastDue", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
ran := new(atomic.Bool)
timer := clock.AfterFunc(500*time.Millisecond, func() { ran.Store(true) })
require.False(t, ran.Load(), "should not complete immediately")
clock.AdvanceTime(9000 * time.Millisecond)
require.True(t, ran.Load(), "should complete when time is reached")
require.False(t, timer.Stop(), "Stop should return false after executing")
})
t.Run("RegisterAsPending", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
ran := new(atomic.Bool)
clock.AfterFunc(500*time.Millisecond, func() { ran.Store(true) })
ctx, cancelFunc := context.WithTimeout(context.Background(), 10*time.Second)
defer cancelFunc()
require.True(t, clock.WaitForNewPendingTask(ctx), "should have added a new pending task")
})
t.Run("DoNotRunIfStopped", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
ran := new(atomic.Bool)
timer := clock.AfterFunc(500*time.Millisecond, func() { ran.Store(true) })
require.False(t, ran.Load(), "should not complete immediately")
require.True(t, timer.Stop(), "Stop should return true on first call")
require.False(t, timer.Stop(), "Stop should return false on subsequent calls")
clock.AdvanceTime(9000 * time.Millisecond)
require.False(t, ran.Load(), "should not run when time is reached")
})
}
func TestNewTicker(t *testing.T) {
t.Run("FiresAfterEachDuration", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
ticker := clock.NewTicker(5 * time.Second)
require.Len(t, ticker.Ch(), 0, "should not fire immediately")
clock.AdvanceTime(4 * time.Second)
require.Len(t, ticker.Ch(), 0, "should not fire before due")
clock.AdvanceTime(1 * time.Second)
require.Len(t, ticker.Ch(), 1, "should fire when due")
require.Equal(t, clock.Now(), <-ticker.Ch(), "should post current time")
clock.AdvanceTime(4 * time.Second)
require.Len(t, ticker.Ch(), 0, "should not re-fire before due")
clock.AdvanceTime(1 * time.Second)
require.Len(t, ticker.Ch(), 1, "should fire when due")
require.Equal(t, clock.Now(), <-ticker.Ch(), "should post current time")
})
t.Run("SkipsFiringWhenAdvancedMultipleDurations", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
ticker := clock.NewTicker(5 * time.Second)
require.Len(t, ticker.Ch(), 0, "should not fire immediately")
// Advance more than three periods, but should still only fire once
clock.AdvanceTime(16 * time.Second)
require.Len(t, ticker.Ch(), 1, "should fire when due")
require.Equal(t, clock.Now(), <-ticker.Ch(), "should post current time")
clock.AdvanceTime(1 * time.Second)
require.Len(t, ticker.Ch(), 0, "should not fire until due again")
})
t.Run("SkipsFiringWhenProcessingIsSlow", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
ticker := clock.NewTicker(5 * time.Second)
// Fire once to fill the channel queue
clock.AdvanceTime(5 * time.Second)
firstEventTime := clock.Now()
var startProcessing sync.WaitGroup
startProcessing.Add(1)
processedTicks := make(chan time.Time)
go func() {
startProcessing.Wait()
// Read two events then exit
for i := 0; i < 2; i++ {
event := <-ticker.Ch()
processedTicks <- event
}
}()
// Advance time further before processing of events has started
// Can't publish any further events to the channel but shouldn't block
clock.AdvanceTime(30 * time.Second)
// Allow processing to start
startProcessing.Done()
require.Equal(t, firstEventTime, <-processedTicks, "Should process first event")
clock.AdvanceTime(5 * time.Second)
require.Equal(t, clock.Now(), <-processedTicks, "Should skip to latest time")
})
t.Run("StopFiring", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
ticker := clock.NewTicker(5 * time.Second)
ticker.Stop()
clock.AdvanceTime(10 * time.Second)
require.Len(t, ticker.Ch(), 0, "should not fire after stop")
})
t.Run("ResetPanicWhenLessNotPositive", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
ticker := clock.NewTicker(5 * time.Second)
require.Panics(t, func() {
ticker.Reset(0)
}, "reset to 0 should panic")
require.Panics(t, func() {
ticker.Reset(-1)
}, "reset to negative duration should panic")
})
t.Run("ResetWithShorterPeriod", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
ticker := clock.NewTicker(5 * time.Second)
require.Len(t, ticker.Ch(), 0, "should not fire immediately")
ticker.Reset(1 * time.Second)
require.Len(t, ticker.Ch(), 0, "should not fire immediately after reset")
clock.AdvanceTime(1 * time.Second)
require.Len(t, ticker.Ch(), 1, "should fire when new duration reached")
require.Equal(t, clock.Now(), <-ticker.Ch(), "should post current time")
})
t.Run("ResetWithLongerPeriod", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
ticker := clock.NewTicker(5 * time.Second)
require.Len(t, ticker.Ch(), 0, "should not fire immediately")
ticker.Reset(7 * time.Second)
require.Len(t, ticker.Ch(), 0, "should not fire immediately after reset")
clock.AdvanceTime(5 * time.Second)
require.Len(t, ticker.Ch(), 0, "should not fire when old duration reached")
clock.AdvanceTime(2 * time.Second)
require.Len(t, ticker.Ch(), 1, "should fire when new duration reached")
require.Equal(t, clock.Now(), <-ticker.Ch(), "should post current time")
})
t.Run("RegisterAsPending", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
ticker := clock.NewTicker(5 * time.Second)
defer ticker.Stop()
ctx, cancelFunc := context.WithTimeout(context.Background(), 10*time.Second)
defer cancelFunc()
require.True(t, clock.WaitForNewPendingTask(ctx), "should have added a new pending task")
})
}
func TestNewTimer(t *testing.T) {
t.Run("FireOnceAfterDuration", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
timer := clock.NewTimer(5 * time.Second)
require.Len(t, timer.Ch(), 0, "should not fire immediately")
clock.AdvanceTime(4 * time.Second)
require.Len(t, timer.Ch(), 0, "should not fire before due")
clock.AdvanceTime(1 * time.Second)
require.Len(t, timer.Ch(), 1, "should fire when due")
require.Equal(t, clock.Now(), <-timer.Ch(), "should post current time")
clock.AdvanceTime(6 * time.Second)
require.Len(t, timer.Ch(), 0, "should not fire when due again")
})
t.Run("StopBeforeExecuted", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
timer := clock.NewTimer(5 * time.Second)
require.True(t, timer.Stop())
clock.AdvanceTime(10 * time.Second)
require.Len(t, timer.Ch(), 0, "should not fire after stop")
})
t.Run("StopAfterExecuted", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
timer := clock.NewTimer(5 * time.Second)
clock.AdvanceTime(10 * time.Second)
require.Len(t, timer.Ch(), 1, "should fire when due")
require.Equal(t, clock.Now(), <-timer.Ch(), "should post current time")
require.False(t, timer.Stop())
})
}
func TestWaitForPending(t *testing.T) {
t.Run("DoNotBlockWhenAlreadyPending", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
_ = clock.After(5 * time.Minute)
_ = clock.After(5 * time.Minute)
ctx, cancelFunc := context.WithTimeout(context.Background(), 10*time.Second)
defer cancelFunc()
require.True(t, clock.WaitForNewPendingTask(ctx), "should have added a new pending task")
})
t.Run("ResetNewPendingFlagAfterWaiting", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
_ = clock.After(5 * time.Minute)
_ = clock.After(5 * time.Minute)
ctx, cancelFunc := context.WithTimeout(context.Background(), 10*time.Second)
defer cancelFunc()
require.True(t, clock.WaitForNewPendingTask(ctx), "should have added a new pending task")
ctx, cancelFunc = context.WithTimeout(context.Background(), 250*time.Millisecond)
defer cancelFunc()
require.False(t, clock.WaitForNewPendingTask(ctx), "should have reset new pending task flag")
})
}
func TestSleepCtx(t *testing.T) {
t.Run("ReturnWhenContextComplete", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
ctx, cancel := context.WithCancel(context.Background())
cancel()
err := clock.SleepCtx(ctx, 5*time.Minute)
require.ErrorIs(t, err, context.Canceled)
})
t.Run("ReturnWhenDurationComplete", func(t *testing.T) {
clock := NewDeterministicClock(time.UnixMilli(1000))
var wg sync.WaitGroup
var result atomic.Value
wg.Add(1)
go func() {
err := clock.SleepCtx(context.Background(), 5*time.Minute)
if err != nil {
result.Store(err)
}
wg.Done()
}()
ctx, cancelFunc := context.WithTimeout(context.Background(), 30*time.Second)
defer cancelFunc()
// Wait until the SleepCtx is called and schedules a pending task
clock.WaitForNewPendingTask(ctx)
clock.AdvanceTime(5 * time.Minute)
// Wait for the call to return
wg.Wait()
require.Nil(t, result.Load())
})
}