expose KubeConfigFromREST in envtest

Signed-off-by: Tiger Kaovilai <tkaovila@redhat.com>

Author: kaovilai

pkg/envtest/server.go

@@ -126,6 +126,12 @@ type Environment struct {
 	// loading.
 	Config *rest.Config
 
+	// KubeConfig provides []byte of a kubeconfig file to talk to the apiserver
+	// It's automatically
+	// populated if not set using the standard controller-runtime config
+	// loading.
+	KubeConfig []byte
+
 	// CRDInstallOptions are the options for installing CRDs.
 	CRDInstallOptions CRDInstallOptions
 
@@ -221,6 +227,10 @@ func (te *Environment) Start() (*rest.Config, error) {
 			if err != nil {
 				return nil, fmt.Errorf("unable to get configuration for existing cluster: %w", err)
 			}
+			te.KubeConfig, err = controlplane.KubeConfigFromREST(te.Config)
+			if err != nil {
+				return nil, fmt.Errorf("unable to convert configuration to kubeconfig: %w", err)
+			}
 		}
 	} else {
 		apiServer := te.ControlPlane.GetAPIServer()