Chore: add basic test for dns utility functions

pkg/dns/dns.go

@@ -42,22 +42,25 @@ func (d *DNSUtil) GetARecords(target string) ([]string, error) {
 	return list, err
 }
 
-func (d *DNSUtil) GetTxtRecords(target string) ([]string, error) {
+func (d *DNSUtil) GetTxtRecords(target string) (list []string, err error) {
 	msg := createQuestion(target, x.TypeTXT)
 
 	result, err := d.makeQuery(msg)
+	if err != nil {
+		return
+	}
 
-	var list []string
+	if len(result.Answer) == 0 {
+		return
+	}
 
-	if len(result.Answer) > 0 {
-		for _, ans := range result.Answer {
-			if t, ok := ans.(*x.TXT); ok {
-				list = append(list, t.Txt...)
-			}
+	for _, ans := range result.Answer {
+		if t, ok := ans.(*x.TXT); ok {
+			list = append(list, t.Txt...)
 		}
 	}
 
-	return list, err
+	return
 }
 
 func (d *DNSUtil) makeQuery(msg *x.Msg) (*x.Msg, error) {

pkg/dns/dns_test.go

@@ -0,0 +1,30 @@
+package dns_test
+
+import (
+	"testing"
+
+	"github.com/Luzilla/dnsbl_exporter/pkg/dns"
+	x "github.com/miekg/dns"
+	"github.com/stretchr/testify/assert"
+	"golang.org/x/exp/slog"
+)
+
+func TestDNSSuite(t *testing.T) {
+	t.Run("test=a", func(t *testing.T) {
+		d := dns.New(new(x.Client), "0.0.0.0:53", slog.Default())
+
+		aRecords, err := d.GetARecords("relay.heise.de")
+
+		assert.NoError(t, err)
+		assert.Greater(t, len(aRecords), 0)
+	})
+
+	t.Run("test=txt", func(t *testing.T) {
+		d := dns.New(new(x.Client), "0.0.0.0:53", slog.Default())
+
+		// DTAG dial-up
+		txtRecords, err := d.GetTxtRecords("85.198.214.79.zen.spamhaus.org")
+		assert.NoError(t, err)
+		assert.Greater(t, len(txtRecords), 0)
+	})
+}