Test caching.

cache_test.go

@@ -3,6 +3,9 @@ package dns_test
 import (
 	"context"
 	"fmt"
+	"net"
+	"testing"
+	"time"
 
 	"github.com/ncruces/go-dns"
 )
@@ -21,3 +24,47 @@ func ExampleNewCachingResolver() {
 	// 2606:4700:4700::1111
 	// 2606:4700:4700::1001
 }
+
+func TestNewCachingResolver(t *testing.T) {
+	// Prime recursive resolver cache.
+	e, err := net.LookupIP("nxdomain.test")
+	if err == nil {
+		t.Errorf("LookupIPAddr('nxdomain.test') = %v", e)
+	}
+
+	r := dns.NewCachingResolver(nil)
+	measure := func() time.Duration {
+		start := time.Now()
+		r.LookupIPAddr(context.TODO(), "nxdomain.test")
+		return time.Since(start)
+	}
+
+	uncached, cached := measure(), measure()
+	if uncached > cached*10 { // Expect order of magnitude difference.
+		t.Logf("uncached %v, cached %v", uncached, cached)
+	} else {
+		t.Errorf("uncached %v, cached %v", uncached, cached)
+	}
+}
+
+func TestNegativeCache(t *testing.T) {
+	// Prime recursive resolver cache.
+	e, err := net.LookupIP("nxdomain.test")
+	if err == nil {
+		t.Errorf("LookupIPAddr('nxdomain.test') = %v", e)
+	}
+
+	r := dns.NewCachingResolver(nil, dns.NegativeCache(false))
+	measure := func() time.Duration {
+		start := time.Now()
+		r.LookupIPAddr(context.TODO(), "nxdomain.test")
+		return time.Since(start)
+	}
+
+	first, second := measure(), measure()
+	if first/10 < second && second < first*10 { // Do not expect huge differences.
+		t.Logf("first %v, second %v", first, second)
+	} else {
+		t.Errorf("first %v, second %v", first, second)
+	}
+}

doh_test.go

@@ -102,7 +102,7 @@ func TestNewDoHResolver(t *testing.T) {
 	})
 }
 
-func TestNewDoH64Resolver(t *testing.T) {
+func TestNewDoHResolver_64(t *testing.T) {
 	// Test IPv6 connectivity (broken on GitHub Actions).
 	if c, err := net.Dial("tcp", "ipv6.google.com:80"); err != nil {
 		t.Skip("IPv6 not supported.")

dot_test.go

@@ -139,7 +139,7 @@ func TestNewDoTResolver(t *testing.T) {
 	})
 }
 
-func TestNewDoT64Resolver(t *testing.T) {
+func TestNewDoTResolver_64(t *testing.T) {
 	// Test IPv6 connectivity (broken on GitHub Actions).
 	if c, err := net.Dial("tcp", "ipv6.google.com:80"); err != nil {
 		t.Skip("IPv6 not supported.")