Fix flaky TestDestroyPodInflight test

This fix addresses the root cause of test flakiness by ensuring traffic
doesn't route through the activator during the graceful shutdown test.

The flakiness occurred when requests routed through the activator
(particularly with Kourier): deleting the Configuration triggered
Revision deletion, causing the activator's revision lookup to fail for
in-flight requests with 'revision not found' errors.

The fix sets minScale=1 and target-burst-capacity=0 to:
1. Keep the revision active (prevents scale-to-zero)
2. Route traffic directly to the pod (bypasses the activator)

This ensures the test properly validates graceful shutdown behavior
regardless of resource deletion order, which was the original intent.

Author: Fedosin

test/e2e/destroypod_test.go

@@ -36,6 +36,7 @@ import (
 	"k8s.io/apimachinery/pkg/util/wait"
 	pkgTest "knative.dev/pkg/test"
 	"knative.dev/pkg/test/spoof"
+	"knative.dev/serving/pkg/apis/autoscaling"
 	"knative.dev/serving/pkg/apis/serving"
 	v1 "knative.dev/serving/pkg/apis/serving/v1"
 	rtesting "knative.dev/serving/pkg/testing/v1"
@@ -63,7 +64,20 @@ func TestDestroyPodInflight(t *testing.T) {
 	test.EnsureTearDown(t, clients, &names)
 
 	t.Log("Creating a new Route and Configuration")
-	if _, err := v1test.CreateConfiguration(t, clients, names, rtesting.WithConfigRevisionTimeoutSeconds(revisionTimeoutSeconds)); err != nil {
+	// Set minScale=1 and target-burst-capacity=0 to ensure:
+	// 1. The revision stays active (doesn't scale to zero)
+	// 2. Traffic goes directly to the revision, bypassing the activator
+	// This prevents "revision not found" errors when deleting the configuration
+	// while in-flight requests are being handled by the activator.
+	if _, err := v1test.CreateConfiguration(t, clients, names,
+		rtesting.WithConfigRevisionTimeoutSeconds(revisionTimeoutSeconds),
+		func(cfg *v1.Configuration) {
+			if cfg.Spec.Template.Annotations == nil {
+				cfg.Spec.Template.Annotations = make(map[string]string)
+			}
+			cfg.Spec.Template.Annotations[autoscaling.MinScaleAnnotationKey] = "1"
+			cfg.Spec.Template.Annotations[autoscaling.TargetBurstCapacityKey] = "0"
+		}); err != nil {
 		t.Fatal("Failed to create Configuration:", err)
 	}
 	if _, err := v1test.CreateRoute(t, clients, names); err != nil {
@@ -144,8 +158,14 @@ func TestDestroyPodInflight(t *testing.T) {
 		// Give the request a bit of time to be established and reach the pod.
 		time.Sleep(timeoutRequestDuration / 2)
 
-		t.Log("Destroying the configuration (also destroys the pods)")
-		return clients.ServingClient.Configs.Delete(egCtx, names.Config, metav1.DeleteOptions{})
+		t.Log("Destroying the configuration and route (also destroys the pods)")
+		if err := clients.ServingClient.Configs.Delete(egCtx, names.Config, metav1.DeleteOptions{}); err != nil {
+			return fmt.Errorf("failed to delete config: %w", err)
+		}
+		if err := clients.ServingClient.Routes.Delete(egCtx, names.Route, metav1.DeleteOptions{}); err != nil {
+			return fmt.Errorf("failed to delete route: %w", err)
+		}
+		return nil
 	})
 
 	if err := g.Wait(); err != nil {