Dealing with testing thinking it is a race in configuration

config.go

@@ -46,4 +46,7 @@ type Config struct {
 
 	// Interfaces will override the interfaces used for queries and answers.
 	Interfaces []net.Interface
+
+	// Override the default behaviour of echoing the query with the answer
+	DoNotEchoQueryWithAnswer bool
 }

conn.go

@@ -37,8 +37,6 @@ type Conn struct {
 	queries       []*query
 	ifaces        map[int]netInterface
 
-	echoQueryInAnswer bool
-
 	closed chan interface{}
 }
 
@@ -104,10 +102,9 @@ func Server(
 	log := loggerFactory.NewLogger("mdns")
 
 	c := &Conn{
-		queryInterval:     defaultQueryInterval,
-		log:               log,
-		closed:            make(chan interface{}),
-		echoQueryInAnswer: true,
+		queryInterval: defaultQueryInterval,
+		log:           log,
+		closed:        make(chan interface{}),
 	}
 	c.name = config.Name
 	if c.name == "" {
@@ -713,7 +710,7 @@ func (c *Conn) writeToSocket(
 	}
 }
 
-func (c *Conn) createAnswer(id uint16, q dnsmessage.Question, addr netip.Addr) (dnsmessage.Message, error) {
+func (c *Conn) createAnswer(id uint16, q dnsmessage.Question, addr netip.Addr, config *Config) (dnsmessage.Message, error) {
 	packedName, err := dnsmessage.NewName(q.Name.String())
 	if err != nil {
 		return dnsmessage.Message{}, err
@@ -736,7 +733,9 @@ func (c *Conn) createAnswer(id uint16, q dnsmessage.Question, addr netip.Addr) (
 		},
 	}
 
-	if c.echoQueryInAnswer {
+	// This is a negative because we want to default to echoing the query with an answer
+	// The main use of turning it off is in testing
+	if !config.DoNotEchoQueryWithAnswer {
 		msg.Questions = []dnsmessage.Question{q}
 	}
 
@@ -764,8 +763,8 @@ func (c *Conn) createAnswer(id uint16, q dnsmessage.Question, addr netip.Addr) (
 	return msg, nil
 }
 
-func (c *Conn) sendAnswer(queryID uint16, q dnsmessage.Question, ifIndex int, result netip.Addr, dst *net.UDPAddr) {
-	answer, err := c.createAnswer(queryID, q, result)
+func (c *Conn) sendAnswer(queryID uint16, q dnsmessage.Question, ifIndex int, result netip.Addr, dst *net.UDPAddr, config *Config) {
+	answer, err := c.createAnswer(queryID, q, result, config)
 	if err != nil {
 		c.log.Warnf("[%s] failed to create mDNS answer %v", c.name, err)
 		return
@@ -1045,7 +1044,7 @@ func (c *Conn) readLoop(name string, pktConn ipPacketConn, inboundBufferSize int
 								continue
 							}
 							c.log.Debugf("[%s] sending response for %s on ifc %d of %s to %s", c.name, q.Name, ifIndex, *localAddress, dst)
-							c.sendAnswer(msg.Header.ID, q, ifIndex, *localAddress, dst)
+							c.sendAnswer(msg.Header.ID, q, ifIndex, *localAddress, dst, config)
 						}
 					}
 				}

conn_test.go

@@ -732,12 +732,11 @@ func testAnswerHandlingWithQueryEchoed(t *testing.T, echoQuery bool) {
 	bSock := createListener4(t)
 
 	aServer, err := Server(ipv4.NewPacketConn(aSock), nil, &Config{
-		LocalNames: []string{"pion-mdns-1.local", "pion-mdns-2.local"},
+		LocalNames:               []string{"pion-mdns-1.local", "pion-mdns-2.local"},
+		DoNotEchoQueryWithAnswer: !echoQuery,
 	})
 	check(err, t)
 
-	aServer.echoQueryInAnswer = echoQuery
-
 	bServer, err := Server(ipv4.NewPacketConn(bSock), nil, &Config{})
 	check(err, t)