fix all the tests

buffer.go

@@ -155,8 +155,9 @@ func (b *buffer) len() int {
 	return len(b.data)
 }
 
-func (b *buffer) flush(w io.Writer, n int) {
-	_, _ = w.Write(b.data[:n])
+func (b *buffer) flush(w io.Writer, n int) error {
+	_, err := w.Write(b.data[:n])
 	n = copy(b.data, b.data[n:])
 	b.data = b.data[:n]
+	return err
 }

datadog/client.go

@@ -125,6 +125,7 @@ func NewClientWith(config ClientConfig) *Client {
 
 	c.bufferSize = newBufSize
 	c.buffer.Serializer = &c.serializer
+	c.serializer.conn = w
 	log.Printf("stats/datadog: sending metrics with a buffer of size %d B", newBufSize)
 	return c
 }

datadog/client_test.go

@@ -109,14 +109,25 @@ func TestClientWithUseDistributions(t *testing.T) {
 	client.Flush()
 
 	expectedPacket1 := "request.count:5|c|#answer:42,hello:world\nrequest.dist_rtt:0.1|d|#answer:42,hello:world\n"
-	assert.EqualValues(t, expectedPacket1, string(<-packets))
+	select {
+	case packet := <-packets:
+		fmt.Println("receive packet", packet)
+		assert.EqualValues(t, expectedPacket1, string(packet))
+	case <-time.After(2 * time.Second):
+		t.Fatal("no response after 2 seconds")
+	}
 
 	client.useDistributions = false
 	client.HandleMeasures(time.Time{}, testMeasure)
 	client.Flush()
 
 	expectedPacket2 := "request.count:5|c|#answer:42,hello:world\nrequest.dist_rtt:0.1|h|#answer:42,hello:world\n"
-	assert.EqualValues(t, expectedPacket2, string(<-packets))
+	select {
+	case packet := <-packets:
+		assert.EqualValues(t, expectedPacket2, string(packet))
+	case <-time.After(2 * time.Second):
+		t.Fatal("no response after 2 seconds")
+	}
 
 	if err := client.Close(); err != nil {
 		t.Error(err)
@@ -236,15 +247,19 @@ func isClosedNetworkConnectionErr(err error) bool {
 // startUDPListener starts a goroutine listening for UDP packets on 127.0.0.1 and an available port.
 // The address listened to is returned as `addr`. The payloads of packets received are copied to `packets`.
 func startUDPListener(t *testing.T, packets chan []byte) (addr string, closer io.Closer) {
-	conn, err := net.ListenPacket("udp", "127.0.0.1:0") // :0 chooses an available port
+	t.Helper()
+	conn, err := net.ListenUDP("udp", &net.UDPAddr{Port: 0, IP: net.ParseIP("127.0.0.1")}) // :0 chooses an available port
 	if err != nil {
 		t.Fatal(err)
 	}
 
+	fmt.Println("starting UDP goroutine")
 	go func() {
 		for {
 			packetBytes := make([]byte, 1024)
+			fmt.Println("call conn.ReadFrom")
 			n, _, err := conn.ReadFrom(packetBytes)
+			fmt.Println("read", n, err)
 			if n > 0 {
 				packets <- packetBytes[:n]
 			}

datadog/serializer.go

@@ -5,7 +5,6 @@ import (
 	"io"
 	"log"
 	"math"
-	"net"
 	"strconv"
 	"strings"
 	"time"
@@ -16,7 +15,7 @@ import (
 // Datagram format: https://docs.datadoghq.com/developers/dogstatsd/datagram_shell
 
 type serializer struct {
-	conn             net.Conn
+	conn             io.WriteCloser
 	bufferSize       int
 	filters          map[string]struct{}
 	distPrefixes     []string

datadog/udp.go

@@ -1,6 +1,9 @@
 package datadog
 
-import "net"
+import (
+	"fmt"
+	"net"
+)
 
 type udpWriter struct {
 	conn net.Conn
@@ -16,6 +19,7 @@ func newUDPWriter(addr string) (*udpWriter, error) {
 	if err != nil {
 		return nil, err
 	}
+	fmt.Printf("udp conn: %#v\n", conn)
 	return &udpWriter{conn: conn}, nil
 
 }
@@ -26,6 +30,7 @@ func (w *udpWriter) Write(data []byte) (int, error) {
 }
 
 func (w *udpWriter) Close() error {
+	fmt.Println("call udpWriter.Close")
 	return w.conn.Close()
 }