Add test case with many buildpods

pkg/build/buildkit/scaler/downscaler.go

@@ -69,6 +69,7 @@ func RunDownscaler(ctx context.Context, clientset kubernetes.Interface, podSelec
 		}
 
 		if usageAt == -1 {
+			maxEndtimeByNS[pod.Namespace] = usageAt
 			continue
 		}
 

pkg/build/buildkit/scaler/downscaler_test.go

@@ -276,3 +276,63 @@ func TestRunDownscalerWithManyPods(t *testing.T) {
 	require.Len(t, rs.Items, 1)
 	assert.Equal(t, int32(0), *rs.Items[0].Spec.Replicas)
 }
+
+func TestRunDownscalerWithManyPods2(t *testing.T) {
+	ctx := context.Background()
+
+	lastBuild := time.Now().Add(-3 * time.Hour).Unix()
+
+	cli := fake.NewSimpleClientset(
+		&corev1.Pod{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      "buildkit-0",
+				Namespace: "default",
+				Labels: map[string]string{
+					"app": "buildkit",
+				},
+
+				Annotations: map[string]string{
+					metadata.DeployAgentLastBuildStartingLabelKey: strconv.Itoa(int(lastBuild)),
+				},
+			},
+			Spec: corev1.PodSpec{},
+		},
+		&corev1.Pod{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      "buildkit-1",
+				Namespace: "default",
+				Labels: map[string]string{
+					"app": "buildkit",
+				},
+
+				Annotations: map[string]string{
+					metadata.DeployAgentLastBuildStartingLabelKey:   strconv.Itoa(int(lastBuild)),
+					metadata.DeployAgentLastBuildEndingTimeLabelKey: strconv.Itoa(int(lastBuild)),
+				},
+			},
+			Spec: corev1.PodSpec{},
+		},
+		&appsv1.StatefulSet{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      "buildkit",
+				Namespace: "default",
+
+				Annotations: map[string]string{
+					metadata.DeployAgentLastReplicasAnnotationKey: "3",
+				},
+			},
+			Spec: appsv1.StatefulSetSpec{
+				Replicas: ptr.To(int32(2)),
+			},
+		},
+	)
+
+	err := RunDownscaler(ctx, cli, "app=buildkit", "buildkit", testGraceful)
+	assert.NoError(t, err)
+
+	rs, err := cli.AppsV1().StatefulSets("").List(ctx, metav1.ListOptions{})
+	assert.NoError(t, err)
+
+	require.Len(t, rs.Items, 1)
+	assert.Equal(t, int32(2), *rs.Items[0].Spec.Replicas)
+}