feat(arp): 自 go-hua 迁入 ARP 表查询与定时刷新缓存

- IP→MAC 查询(AutoRefresh 后台刷新/Search/Table), 新增依赖 mostlygeek/arp
- 附测试、examples/arp 例程与包 README

arp/arp_test.go

@@ -0,0 +1,94 @@
+package arp
+
+import (
+	"fmt"
+	"testing"
+	"time"
+)
+
+var (
+	_ = fmt.Println
+)
+
+func TestTable(t *testing.T) {
+
+	table := Table()
+	if table == nil {
+		t.Errorf("Empty table")
+	}
+}
+
+func TestCacheInfo(t *testing.T) {
+	prevUpdated := CacheLastUpdate().UnixNano()
+	prevCount := CacheUpdateCount()
+
+	CacheUpdate()
+
+	if prevUpdated == CacheLastUpdate().UnixNano() {
+		t.Error()
+	}
+
+	if prevCount == CacheUpdateCount() {
+		t.Error()
+	}
+}
+
+func TestAutoRefresh(t *testing.T) {
+	if testing.Short() {
+		t.Skip("Skipping autorefresh test")
+	}
+	prevUpdated := CacheLastUpdate().UnixNano()
+	prevCount := CacheUpdateCount()
+
+	AutoRefresh(100 * time.Millisecond)
+	time.Sleep(200 * time.Millisecond)
+	StopAutoRefresh()
+
+	if prevUpdated == CacheLastUpdate().UnixNano() {
+		t.Error()
+	}
+
+	if prevCount == CacheUpdateCount() {
+		t.Error()
+	}
+
+	// test to make sure stop worked
+	prevUpdated = CacheLastUpdate().UnixNano()
+	prevCount = CacheUpdateCount()
+	time.Sleep(200 * time.Millisecond)
+	if prevUpdated != CacheLastUpdate().UnixNano() {
+		t.Error()
+	}
+
+	if prevCount != CacheUpdateCount() {
+		t.Error()
+	}
+}
+
+func TestSearch(t *testing.T) {
+	table := Table()
+
+	for ip, test := range table {
+
+		result := Search(ip)
+		if test != result {
+			t.Errorf("expected %s got %s", test, result)
+		}
+	}
+}
+
+func BenchmarkSearch(b *testing.B) {
+	table := Table()
+	if len(table) == 0 {
+		return
+	}
+
+	for ip, _ := range Table() {
+		for i := 0; i < b.N; i++ {
+			Search(ip)
+		}
+
+		// using the first key is enough
+		break
+	}
+}