From 60da931e0e6bdc4f102ff7440bee240f0f63c01c Mon Sep 17 00:00:00 2001
From: Jan Chaloupka <jchaloup@redhat.com>
Date: Thu, 18 Dec 2025 16:50:09 +0100
Subject: [PATCH] fix(TestReadyNodesWithNodeSelector): make sure
 nodeLister.List always returns a non-empty list so the lister is always
 tested

The case of an empty list of nodes from the lister is not easy to catch.
This change makes sure one more initial condition is met.
---
 pkg/descheduler/node/node_test.go | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/pkg/descheduler/node/node_test.go b/pkg/descheduler/node/node_test.go
index a25786722..6b9e93cac 100644
--- a/pkg/descheduler/node/node_test.go
+++ b/pkg/descheduler/node/node_test.go
@@ -25,6 +25,7 @@ import (
 	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/resource"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/labels"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/client-go/informers"
 	"k8s.io/client-go/kubernetes/fake"
@@ -79,9 +80,24 @@ func TestReadyNodesWithNodeSelector(t *testing.T) {
 	sharedInformerFactory.WaitForCacheSync(stopChannel)
 	defer close(stopChannel)
 
+	// First verify nodeLister returns non-empty list
+	allNodes, err := nodeLister.List(labels.Everything())
+	if err != nil {
+		t.Fatalf("Failed to list nodes from nodeLister: %v", err)
+	}
+	if len(allNodes) == 0 {
+		t.Fatal("Expected nodeLister to return non-empty list of nodes")
+	}
+	if len(allNodes) != 2 {
+		t.Errorf("Expected nodeLister to return 2 nodes, got %d", len(allNodes))
+	}
+
+	// Now test ReadyNodes
 	nodes, _ := ReadyNodes(ctx, fakeClient, nodeLister, nodeSelector)
 
-	if nodes[0].Name != "node1" {
+	if len(nodes) != 1 {
+		t.Errorf("Expected 1 node, got %d", len(nodes))
+	} else if nodes[0].Name != "node1" {
 		t.Errorf("Expected node1, got %s", nodes[0].Name)
 	}
 }