Add MAC validation checker and tests to v2. (#139)

# Describe Request

Add MAC validation checker and tests to v2.

# Change Type

New code.

v2/mac.go

@@ -0,0 +1,41 @@
+// Copyright (c) 2023-2024 Onur Cinar.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+// https://github.com/cinar/checker
+
+package v2
+
+import (
+	"net"
+	"reflect"
+)
+
+const (
+	// nameMAC is the name of the MAC check.
+	nameMAC = "mac"
+)
+
+var (
+	// ErrNotMAC indicates that the given value is not a valid MAC address.
+	ErrNotMAC = NewCheckError("MAC")
+)
+
+// IsMAC checks if the value is a valid MAC address.
+func IsMAC(value string) (string, error) {
+	_, err := net.ParseMAC(value)
+	if err != nil {
+		return value, ErrNotMAC
+	}
+	return value, nil
+}
+
+// checkMAC checks if the value is a valid MAC address.
+func checkMAC(value reflect.Value) (reflect.Value, error) {
+	_, err := IsMAC(value.Interface().(string))
+	return value, err
+}
+
+// makeMAC makes a checker function for the MAC checker.
+func makeMAC(_ string) CheckFunc[reflect.Value] {
+	return checkMAC
+}

v2/mac_test.go

@@ -0,0 +1,76 @@
+// Copyright (c) 2023-2024 Onur Cinar.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+// https://github.com/cinar/checker
+
+package v2_test
+
+import (
+	"fmt"
+	"testing"
+
+	v2 "github.com/cinar/checker/v2"
+)
+
+func ExampleIsMAC() {
+	_, err := v2.IsMAC("00:1A:2B:3C:4D:5E")
+	if err != nil {
+		fmt.Println(err)
+	}
+}
+
+func TestIsMACInvalid(t *testing.T) {
+	_, err := v2.IsMAC("invalid-mac")
+	if err == nil {
+		t.Fatal("expected error")
+	}
+}
+
+func TestIsMACValid(t *testing.T) {
+	_, err := v2.IsMAC("00:1A:2B:3C:4D:5E")
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestCheckMACNonString(t *testing.T) {
+	defer FailIfNoPanic(t, "expected panic")
+
+	type Device struct {
+		MAC int `checkers:"mac"`
+	}
+
+	device := &Device{}
+
+	v2.CheckStruct(device)
+}
+
+func TestCheckMACInvalid(t *testing.T) {
+	type Device struct {
+		MAC string `checkers:"mac"`
+	}
+
+	device := &Device{
+		MAC: "invalid-mac",
+	}
+
+	_, ok := v2.CheckStruct(device)
+	if ok {
+		t.Fatal("expected error")
+	}
+}
+
+func TestCheckMACValid(t *testing.T) {
+	type Device struct {
+		MAC string `checkers:"mac"`
+	}
+
+	device := &Device{
+		MAC: "00:1A:2B:3C:4D:5E",
+	}
+
+	_, ok := v2.CheckStruct(device)
+	if !ok {
+		t.Fatal("expected valid")
+	}
+}

v2/maker.go

@@ -27,6 +27,7 @@ var makers = map[string]MakeCheckFunc{
 	nameIPv6:         makeIPv6,
 	nameISBN:         makeISBN,
 	nameLUHN:         makeLUHN,
+	nameMAC:          makeMAC,
 	nameMaxLen:       makeMaxLen,
 	nameMinLen:       makeMinLen,
 	nameRequired:     makeRequired,