Fix back off when scheduling cycle is delayed

Signed-off-by: Aldo Culquicondor <acondor@google.com>

pkg/scheduler/internal/queue/scheduling_queue_test.go

@@ -1515,3 +1515,85 @@ func createAndRunPriorityQueue(fwk framework.Framework, opts ...Option) *Priorit
 	q.Run()
 	return q
 }
+
+func TestBackOffFlow(t *testing.T) {
+	cl := clock.NewFakeClock(time.Now())
+	q := NewPriorityQueue(newDefaultFramework(), WithClock(cl))
+	steps := []struct {
+		wantBackoff time.Duration
+	}{
+		{wantBackoff: time.Second},
+		{wantBackoff: 2 * time.Second},
+		{wantBackoff: 4 * time.Second},
+		{wantBackoff: 8 * time.Second},
+		{wantBackoff: 10 * time.Second},
+		{wantBackoff: 10 * time.Second},
+		{wantBackoff: 10 * time.Second},
+	}
+	pod := &v1.Pod{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "test-pod",
+			Namespace: "test-ns",
+			UID:       "test-uid",
+		},
+	}
+	podID := nsNameForPod(pod)
+	if err := q.Add(pod); err != nil {
+		t.Fatal(err)
+	}
+
+	for i, step := range steps {
+		t.Run(fmt.Sprintf("step %d", i), func(t *testing.T) {
+			timestamp := cl.Now()
+			// Simulate schedule attempt.
+			podInfo, err := q.Pop()
+			if err != nil {
+				t.Fatal(err)
+			}
+			if podInfo.Attempts != i+1 {
+				t.Errorf("got attempts %d, want %d", podInfo.Attempts, i+1)
+			}
+			if err := q.AddUnschedulableIfNotPresent(podInfo, int64(i)); err != nil {
+				t.Fatal(err)
+			}
+
+			// An event happens.
+			q.MoveAllToActiveOrBackoffQueue("deleted pod")
+
+			if _, ok, _ := q.podBackoffQ.Get(podInfo); !ok {
+				t.Errorf("pod %v is not in the backoff queue", podID)
+			}
+
+			// Check backoff duration.
+			deadline, ok := q.podBackoff.GetBackoffTime(podID)
+			if !ok {
+				t.Errorf("didn't get backoff for pod %s", podID)
+			}
+			backoff := deadline.Sub(timestamp)
+			if backoff != step.wantBackoff {
+				t.Errorf("got backoff %s, want %s", backoff, step.wantBackoff)
+			}
+
+			// Simulate routine that continuously flushes the backoff queue.
+			cl.Step(time.Millisecond)
+			q.flushBackoffQCompleted()
+			// Still in backoff queue after an early flush.
+			if _, ok, _ := q.podBackoffQ.Get(podInfo); !ok {
+				t.Errorf("pod %v is not in the backoff queue", podID)
+			}
+			// Moved out of the backoff queue after timeout.
+			cl.Step(backoff)
+			q.flushBackoffQCompleted()
+			if _, ok, _ := q.podBackoffQ.Get(podInfo); ok {
+				t.Errorf("pod %v is still in the backoff queue", podID)
+			}
+		})
+	}
+	// After some time, backoff information is cleared.
+	cl.Step(time.Hour)
+	q.podBackoff.CleanupPodsCompletesBackingoff()
+	_, ok := q.podBackoff.GetBackoffTime(podID)
+	if ok {
+		t.Errorf("backoff information for pod %s was not cleared", podID)
+	}
+}