diff --git a/errors.go b/errors.go
index 2fc1c87..8576e26 100644
--- a/errors.go
+++ b/errors.go
@@ -140,6 +140,6 @@ var (
 	errNotImplemented                = errors.New("not implemented yet")
 	errNoUDPMuxAvailable             = errors.New("no UDP mux is available")
 	errNoTCPMuxAvailable             = errors.New("no TCP mux is available")
-	errListenUnspecified             = errors.New("can't listen on unspecified address")
-	errInvalidAddress                = errors.New("invalid address")
+	// errListenUnspecified             = errors.New("can't listen on unspecified address")
+	errInvalidAddress = errors.New("invalid address")
 )
diff --git a/udp_mux_test.go b/udp_mux_test.go
index 16d44d1..36192ae 100644
--- a/udp_mux_test.go
+++ b/udp_mux_test.go
@@ -33,75 +33,35 @@ func TestUDPMux(t *testing.T) {
 		t.Log("IPv6 is not supported on this machine")
 	}
 
-	for network, c := range map[string]net.PacketConn{udp4: conn4, udp6: conn6} {
-		if udpConn, ok := c.(*net.UDPConn); !ok || udpConn == nil {
-			continue
-		}
-		conn := c
-		t.Run(network, func(t *testing.T) {
-			udpMux, err := NewUDPMuxDefault(UDPMuxParams{
-				Logger:  nil,
-				UDPConn: conn,
-			})
-
-			require.NoError(t, err)
-
-			defer func() {
-				_ = udpMux.Close()
-				_ = conn.Close()
-			}()
-
-			require.NotNil(t, udpMux.LocalAddr(), "udpMux.LocalAddr() is nil")
-
-			wg := sync.WaitGroup{}
-
-			wg.Add(1)
-			go func() {
-				defer wg.Done()
-				testMuxConnection(t, udpMux, "ufrag1", udp)
-			}()
-
-			// skip ipv6 test on i386
-			const ptrSize = 32 << (^uintptr(0) >> 63)
-			if ptrSize != 32 || network != udp6 {
-				testMuxConnection(t, udpMux, "ufrag2", network)
-			}
-
-			wg.Wait()
-
-			require.NoError(t, udpMux.Close())
-
-			// can't create more connections
-			_, err = udpMux.GetConn("failufrag", udpMux.LocalAddr())
-			require.Error(t, err)
-		})
-	}
-}
-
-func TestUDPMuxUnspecifiedAddr(t *testing.T) {
-	report := test.CheckRoutines(t)
-	defer report()
-
-	lim := test.TimeOut(time.Second * 30)
-	defer lim.Stop()
-
-	conn, err := net.ListenUDP(udp, nil)
+	connUnspecified, err := net.ListenUDP(udp, nil)
 	require.NoError(t, err)
 
-	conn4, err := net.ListenUDP(udp, &net.UDPAddr{IP: net.IPv4zero})
+	conn4Unspecified, err := net.ListenUDP(udp, &net.UDPAddr{IP: net.IPv4zero})
 	require.NoError(t, err)
 
-	conn6, err := net.ListenUDP(udp, &net.UDPAddr{IP: net.IPv6unspecified})
+	conn6Unspecified, err := net.ListenUDP(udp, &net.UDPAddr{IP: net.IPv6unspecified})
 	if err != nil {
 		t.Log("IPv6 is not supported on this machine")
 	}
 
-	for network, c := range map[string]net.PacketConn{udp: conn, udp4: conn4, udp6: conn6} {
-		if udpConn, ok := c.(*net.UDPConn); !ok || udpConn == nil {
+	type testCase struct {
+		name    string
+		conn    net.PacketConn
+		network string
+	}
+
+	for _, subTest := range []testCase{
+		{name: "IPv4loopback", conn: conn4, network: udp4},
+		{name: "IPv6loopback", conn: conn6, network: udp6},
+		{name: "Unspecified", conn: connUnspecified, network: udp},
+		{name: "IPv4Unspecified", conn: conn4Unspecified, network: udp4},
+		{name: "IPv6Unspecified", conn: conn6Unspecified, network: udp6},
+	} {
+		network, conn := subTest.network, subTest.conn
+		if udpConn, ok := conn.(*net.UDPConn); !ok || udpConn == nil {
 			continue
 		}
-		conn := c
-		t.Run(network, func(t *testing.T) {
+		t.Run(subTest.name, func(t *testing.T) {
 			udpMux, err := NewUDPMuxDefault(UDPMuxParams{
 				Logger:  nil,
 				UDPConn: conn,
@@ -124,9 +84,18 @@ func TestUDPMuxUnspecifiedAddr(t *testing.T) {
 				testMuxConnection(t, udpMux, "ufrag1", udp)
 			}()
 
-			// skip ipv6 test on i386
 			const ptrSize = 32 << (^uintptr(0) >> 63)
-			if ptrSize != 32 || network != udp6 {
+			if network == udp {
+				wg.Add(1)
+				go func() {
+					defer wg.Done()
+					testMuxConnection(t, udpMux, "ufrag2", udp4)
+				}()
+				// skip ipv6 test on i386
+				if ptrSize != 32 {
+					testMuxConnection(t, udpMux, "ufrag3", udp6)
+				}
+			} else if ptrSize != 32 || network != udp6 {
 				testMuxConnection(t, udpMux, "ufrag2", network)
 			}