add test in cmd/kubeadm/app/apis/kubeadm/validation/validation_test.go for ValidatePort

modify

cmd/kubeadm/app/apis/kubeadm/validation/validation_test.go

@@ -18,6 +18,7 @@ package validation
 
 import (
 	"os"
+	"strings"
 	"testing"
 
 	"github.com/spf13/pflag"
@@ -183,6 +184,34 @@ func TestValidateIPFromString(t *testing.T) {
 	}
 }
 
+func TestValidatePort(t *testing.T) {
+	var tests = []struct {
+		name        string
+		port        int32
+		expectedErr bool
+	}{
+		{"negative number port", -1234, true},
+		{"zero number port", 0, true},
+		{"minimum valid value port", 1, false},
+		{"valid value port", 300, false},
+		{"maximum valid value port", 65535, false},
+		{"if port greater than 65535", 65538, true},
+	}
+	for _, rt := range tests {
+		t.Run(rt.name, func(t *testing.T) {
+			allErrs := ValidatePort(rt.port, nil)
+			if len(allErrs) > 0 {
+				find := strings.Contains(allErrs[0].Error(), "port number is not valid")
+				if find != rt.expectedErr {
+					t.Errorf(
+						"test case failed :\n\t   err(s): %v\n\t", allErrs[0].Error(),
+					)
+				}
+			}
+		})
+	}
+}
+
 func TestValidateIPNetFromString(t *testing.T) {
 	var tests = []struct {
 		name     string