Fixed failing test

pkg/zdns/lookup_test.go

@@ -19,8 +19,6 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
-
-	"github.com/zmap/dns"
 )
 
 type domain_ns struct {
@@ -57,13 +55,10 @@ func InitTest(t *testing.T) *Resolver {
 	protocolStatus = make(map[domain_ns]Status)
 	mockResults = make(map[domain_ns]SingleQueryResult)
 
-	r := Resolver{
-		nameServers: []string{"127.0.0.1"},
-		udpClient:   new(dns.Client),
-	}
 	mc := MockLookupClient{}
-	r.WithLookuper(mc)
-	return &r
+	r, err := NewResolverBuilder().WithNameServers([]string{"127.0.0.1"}).WithLookuper(mc).BuildExternalResolver()
+	assert.NoError(t, err)
+	return r
 }
 
 // Test specifying neither ipv4 not ipv6 flag looks up ipv4 by default

pkg/zdns/resolver_configurer.go

@@ -200,7 +200,7 @@ func (rc *ResolverConfigurer) BuildIterativeResolver(cache *Cache) (*Resolver, e
 }
 
 // isValid checks if the resolver is valid
-// Returns true, nil or false, error where error describes what is invalid about the resolver configurer. Called before building the resolver
+// Returns whether the resolver configurer is valid or not and if invalid, why. Called before building the resolver.
 func (rc *ResolverConfigurer) isValid() (bool, string) {
 	if rc.hasBeenBuilt {
 		return false, "cannot change resolver builder after resolver has been built"
@@ -213,8 +213,8 @@ func (rc *ResolverConfigurer) isValid() (bool, string) {
 
 // buildResolverHelper has the common build logic for all resolvers
 func (rc *ResolverConfigurer) buildResolverHelper() (*Resolver, error) {
-	if isValid, err := rc.isValid(); !isValid {
-		return nil, fmt.Errorf("invalid resolver: %w", err)
+	if isValid, notValidReason := rc.isValid(); !isValid {
+		return nil, fmt.Errorf("invalid resolver: %s", notValidReason)
 	}
 	log.SetLevel(rc.r.logLevel)
 	if !rc.localAddrSet {