pkg/karmadactl: unit test join

In this commit, we unit test the process of joining a cluster
to the Karmada control plane. The tests validate the arguments
passed to the join cluster operation and ensure the creation of
the new cluster runtime object. Additionally, we verify that the
necessary access secrets for the new cluster in push mode are correctly
generated in the Karmada control plane.

Signed-off-by: Mohamed Awnallah <[email protected]>

pkg/karmadactl/join/join.go

@@ -17,6 +17,7 @@ limitations under the License.
 package join
 
 import (
+	"errors"
 	"fmt"
 	"strings"
 
@@ -135,10 +136,10 @@ func (j *CommandJoinOption) Complete(args []string) error {
 // Validate checks option and return a slice of found errs.
 func (j *CommandJoinOption) Validate(args []string) error {
 	if len(args) > 1 {
-		return fmt.Errorf("only the cluster name is allowed as an argument")
+		return errors.New("only the cluster name is allowed as an argument")
 	}
 	if len(j.ClusterName) == 0 {
-		return fmt.Errorf("cluster name is required")
+		return errors.New("cluster name is required")
 	}
 	if errMsgs := validation.ValidateClusterName(j.ClusterName); len(errMsgs) != 0 {
 		return fmt.Errorf("invalid cluster name(%s): %s", j.ClusterName, strings.Join(errMsgs, ";"))
@@ -196,11 +197,21 @@ func (j *CommandJoinOption) Run(f cmdutil.Factory) error {
 	return j.RunJoinCluster(controlPlaneRestConfig, clusterConfig)
 }
 
+var controlPlaneKubeClientBuilder = func(controlPlaneRestConfig *rest.Config) kubeclient.Interface {
+	return kubeclient.NewForConfigOrDie(controlPlaneRestConfig)
+}
+var karmadaClientBuilder = func(controlPlaneRestConfig *rest.Config) karmadaclientset.Interface {
+	return karmadaclientset.NewForConfigOrDie(controlPlaneRestConfig)
+}
+var clusterKubeClientBuilder = func(clusterConfig *rest.Config) kubeclient.Interface {
+	return kubeclient.NewForConfigOrDie(clusterConfig)
+}
+
 // RunJoinCluster join the cluster into karmada.
 func (j *CommandJoinOption) RunJoinCluster(controlPlaneRestConfig, clusterConfig *rest.Config) (err error) {
-	controlPlaneKubeClient := kubeclient.NewForConfigOrDie(controlPlaneRestConfig)
-	karmadaClient := karmadaclientset.NewForConfigOrDie(controlPlaneRestConfig)
-	clusterKubeClient := kubeclient.NewForConfigOrDie(clusterConfig)
+	controlPlaneKubeClient := controlPlaneKubeClientBuilder(controlPlaneRestConfig)
+	karmadaClient := karmadaClientBuilder(controlPlaneRestConfig)
+	clusterKubeClient := clusterKubeClientBuilder(clusterConfig)
 
 	klog.V(1).Infof("Joining cluster config. endpoint: %s", clusterConfig.Host)
 
@@ -288,7 +299,7 @@ func generateClusterInControllerPlane(opts util.ClusterRegisterOption) (*cluster
 		clusterObj.Spec.ProxyURL = url.String()
 	}
 
-	controlPlaneKarmadaClient := karmadaclientset.NewForConfigOrDie(opts.ControlPlaneConfig)
+	controlPlaneKarmadaClient := karmadaClientBuilder(opts.ControlPlaneConfig)
 	cluster, err := util.CreateClusterObject(controlPlaneKarmadaClient, clusterObj)
 	if err != nil {
 		return nil, fmt.Errorf("failed to create cluster(%s) object. error: %v", opts.ClusterName, err)