Merge pull request #80955 from MikeSpreitzer/add-event-clock

Factor PassiveClock out of clock.Clock

staging/src/k8s.io/apimachinery/pkg/util/clock/clock.go

@@ -21,11 +21,18 @@ import (
 	"time"
 )
 
+// PassiveClock allows for injecting fake or real clocks into code
+// that needs to read the current time but does not support scheduling
+// activity in the future.
+type PassiveClock interface {
+	Now() time.Time
+	Since(time.Time) time.Duration
+}
+
 // Clock allows for injecting fake or real clocks into code that
 // needs to do arbitrary things based on time.
 type Clock interface {
-	Now() time.Time
-	Since(time.Time) time.Duration
+	PassiveClock
 	After(time.Duration) <-chan time.Time
 	NewTimer(time.Duration) Timer
 	Sleep(time.Duration)
@@ -66,10 +73,15 @@ func (RealClock) Sleep(d time.Duration) {
 	time.Sleep(d)
 }
 
-// FakeClock implements Clock, but returns an arbitrary time.
-type FakeClock struct {
+// FakePassiveClock implements PassiveClock, but returns an arbitrary time.
+type FakePassiveClock struct {
 	lock sync.RWMutex
 	time time.Time
+}
+
+// FakeClock implements Clock, but returns an arbitrary time.
+type FakeClock struct {
+	FakePassiveClock
 
 	// waiters are waiting for the fake time to pass their specified time
 	waiters []fakeClockWaiter
@@ -82,26 +94,39 @@ type fakeClockWaiter struct {
 	destChan      chan time.Time
 }
 
-func NewFakeClock(t time.Time) *FakeClock {
-	return &FakeClock{
+func NewFakePassiveClock(t time.Time) *FakePassiveClock {
+	return &FakePassiveClock{
 		time: t,
 	}
 }
 
+func NewFakeClock(t time.Time) *FakeClock {
+	return &FakeClock{
+		FakePassiveClock: *NewFakePassiveClock(t),
+	}
+}
+
 // Now returns f's time.
-func (f *FakeClock) Now() time.Time {
+func (f *FakePassiveClock) Now() time.Time {
 	f.lock.RLock()
 	defer f.lock.RUnlock()
 	return f.time
 }
 
 // Since returns time since the time in f.
-func (f *FakeClock) Since(ts time.Time) time.Duration {
+func (f *FakePassiveClock) Since(ts time.Time) time.Duration {
 	f.lock.RLock()
 	defer f.lock.RUnlock()
 	return f.time.Sub(ts)
 }
 
+// Sets the time.
+func (f *FakePassiveClock) SetTime(t time.Time) {
+	f.lock.Lock()
+	defer f.lock.Unlock()
+	f.time = t
+}
+
 // Fake version of time.After(d).
 func (f *FakeClock) After(d time.Duration) <-chan time.Time {
 	f.lock.Lock()

staging/src/k8s.io/apimachinery/pkg/util/clock/clock_test.go

@@ -33,20 +33,50 @@ var (
 	_ = Ticker(&fakeTicker{})
 )
 
+type SettablePassiveClock interface {
+	PassiveClock
+	SetTime(time.Time)
+}
+
+func exercisePassiveClock(t *testing.T, pc SettablePassiveClock) {
+	t1 := time.Now()
+	t2 := t1.Add(time.Hour)
+	pc.SetTime(t1)
+	tx := pc.Now()
+	if tx != t1 {
+		t.Errorf("SetTime(%#+v); Now() => %#+v", t1, tx)
+	}
+	dx := pc.Since(t1)
+	if dx != 0 {
+		t.Errorf("Since() => %v", dx)
+	}
+	pc.SetTime(t2)
+	dx = pc.Since(t1)
+	if dx != time.Hour {
+		t.Errorf("Since() => %v", dx)
+	}
+	tx = pc.Now()
+	if tx != t2 {
+		t.Errorf("Now() => %#+v", tx)
+	}
+}
+
+func TestFakePassiveClock(t *testing.T) {
+	startTime := time.Now()
+	tc := NewFakePassiveClock(startTime)
+	exercisePassiveClock(t, tc)
+}
+
 func TestFakeClock(t *testing.T) {
 	startTime := time.Now()
 	tc := NewFakeClock(startTime)
+	exercisePassiveClock(t, tc)
+	tc.SetTime(startTime)
 	tc.Step(time.Second)
 	now := tc.Now()
 	if now.Sub(startTime) != time.Second {
 		t.Errorf("input: %s now=%s gap=%s expected=%s", startTime, now, now.Sub(startTime), time.Second)
 	}
-
-	tt := tc.Now()
-	tc.SetTime(tt.Add(time.Hour))
-	if tc.Since(tt) != time.Hour {
-		t.Errorf("input: %s now=%s gap=%s expected=%s", tt, tc.Now(), tc.Since(tt), time.Hour)
-	}
 }
 
 func TestFakeClockSleep(t *testing.T) {