Add a function to ensure created nodes are present in scheduler cache

test/integration/scheduler/util.go

@@ -111,7 +111,7 @@ func initTestDisablePreemption(t *testing.T, nsPrefix string) *testutils.TestCon
 // to see is in the store. Used to observe reflected events.
 func waitForReflection(t *testing.T, nodeLister corelisters.NodeLister, key string,
 	passFunc func(n interface{}) bool) error {
-	nodes := []*v1.Node{}
+	var nodes []*v1.Node
 	err := wait.Poll(time.Millisecond*100, wait.ForeverTestTimeout, func() (bool, error) {
 		n, err := nodeLister.Get(key)
 
@@ -143,6 +143,9 @@ func createNode(cs clientset.Interface, node *v1.Node) (*v1.Node, error) {
 
 // createNodes creates `numNodes` nodes. The created node names will be in the
 // form of "`prefix`-X" where X is an ordinal.
+// DEPRECATED
+// use createAndWaitForNodesInCache instead, which ensures the created nodes
+// to be present in scheduler cache.
 func createNodes(cs clientset.Interface, prefix string, wrapper *st.NodeWrapper, numNodes int) ([]*v1.Node, error) {
 	nodes := make([]*v1.Node, numNodes)
 	for i := 0; i < numNodes; i++ {
@@ -156,6 +159,29 @@ func createNodes(cs clientset.Interface, prefix string, wrapper *st.NodeWrapper,
 	return nodes[:], nil
 }
 
+// createAndWaitForNodesInCache calls createNodes(), and wait for the created
+// nodes to be present in scheduler cache.
+func createAndWaitForNodesInCache(testCtx *testutils.TestContext, prefix string, wrapper *st.NodeWrapper, numNodes int) ([]*v1.Node, error) {
+	existingNodes := testCtx.Scheduler.SchedulerCache.NodeCount()
+	nodes, err := createNodes(testCtx.ClientSet, prefix, wrapper, numNodes)
+	if err != nil {
+		return nodes, fmt.Errorf("cannot create nodes: %v", err)
+	}
+	return nodes, waitForNodesInCache(testCtx.Scheduler, numNodes+existingNodes)
+}
+
+// waitForNodesInCache ensures at least <nodeCount> nodes are present in scheduler cache
+// within 30 seconds; otherwise returns false.
+func waitForNodesInCache(sched *scheduler.Scheduler, nodeCount int) error {
+	err := wait.Poll(100*time.Millisecond, wait.ForeverTestTimeout, func() (bool, error) {
+		return sched.SchedulerCache.NodeCount() >= nodeCount, nil
+	})
+	if err != nil {
+		return fmt.Errorf("cannot obtain available nodes in scheduler cache: %v", err)
+	}
+	return nil
+}
+
 type pausePodConfig struct {
 	Name                              string
 	Namespace                         string