Fix flaky TestDestroyPodInflight test

Fixes three issues causing test flakiness:

1. Fix response body reading - use io.ReadAll instead of incorrectly
   casting res.Body to string
2. Add proper response body cleanup with defer
3. Delete Route before Configuration to prevent reconciliation errors
   during teardown (fixes "revision not found" and "failed to fetch
   loadbalancer" errors in CI logs)

The test now correctly validates that in-flight requests complete
successfully during graceful shutdown.

Author: Fedosin

test/e2e/destroypod_test.go

@@ -22,6 +22,7 @@ package e2e
 import (
 	"context"
 	"fmt"
+	"io"
 	"net/http"
 	"net/url"
 	"strconv"
@@ -128,12 +129,19 @@ func TestDestroyPodInflight(t *testing.T) {
 		if err != nil {
 			return err
 		}
+		defer res.Body.Close()
 
 		if res.StatusCode != http.StatusOK {
 			return fmt.Errorf("expected response to have status 200, had %d", res.StatusCode)
 		}
+
+		bodyBytes, err := io.ReadAll(res.Body)
+		if err != nil {
+			return fmt.Errorf("failed to read response body: %w", err)
+		}
+
 		expectedBody := fmt.Sprintf("Slept for %d milliseconds", timeoutRequestDuration.Milliseconds())
-		gotBody := string(res.Body)
+		gotBody := string(bodyBytes)
 		if gotBody != expectedBody {
 			return fmt.Errorf("unexpected body, expected: %q got: %q", expectedBody, gotBody)
 		}
@@ -144,8 +152,16 @@ 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 route and configuration (also destroys the pods)")
+		// Delete the Route first to prevent reconciliation errors during cleanup
+		if err := clients.ServingClient.Routes.Delete(egCtx, names.Route, metav1.DeleteOptions{}); err != nil {
+			return fmt.Errorf("failed to delete route: %w", err)
+		}
+		// Then delete the Configuration
+		if err := clients.ServingClient.Configs.Delete(egCtx, names.Config, metav1.DeleteOptions{}); err != nil {
+			return fmt.Errorf("failed to delete config: %w", err)
+		}
+		return nil
 	})
 
 	if err := g.Wait(); err != nil {