diff --git a/go.mod b/go.mod
index e37b172..3b9ae58 100644
--- a/go.mod
+++ b/go.mod
@@ -5,11 +5,11 @@ go 1.12
 require (
 	github.com/Yawning/chacha20 v0.0.0-20170904085104-e3b1f968fc63 // indirect
 	github.com/boltdb/bolt v1.3.1
+	github.com/cbeuw/connutil v0.0.0-20200407140739-52c0cf88d537
 	github.com/gorilla/mux v1.7.3
 	github.com/gorilla/websocket v1.4.1
 	github.com/juju/ratelimit v1.0.1
 	github.com/kr/pretty v0.1.0 // indirect
-	github.com/mitchellh/gox v1.0.1 // indirect
 	github.com/refraction-networking/utls v0.0.0-20190824032329-cc2996c81813
 	github.com/sirupsen/logrus v1.4.2
 	golang.org/x/crypto v0.0.0-20190701094942-4def268fd1a4
diff --git a/go.sum b/go.sum
index 9dcb2e4..761cc10 100644
--- a/go.sum
+++ b/go.sum
@@ -2,14 +2,14 @@ github.com/Yawning/chacha20 v0.0.0-20170904085104-e3b1f968fc63 h1:I6/SJSN9wJMJ+Z
 github.com/Yawning/chacha20 v0.0.0-20170904085104-e3b1f968fc63/go.mod h1:nf+Komq6fVP4SwmKEaVGxHTyQGKREVlwjQKpvOV39yE=
 github.com/boltdb/bolt v1.3.1 h1:JQmyP4ZBrce+ZQu0dY660FMfatumYDLun9hBCUVIkF4=
 github.com/boltdb/bolt v1.3.1/go.mod h1:clJnj/oiGkjum5o1McbSZDSLxVThjynRyGBgiAx27Ps=
+github.com/cbeuw/connutil v0.0.0-20200407140739-52c0cf88d537 h1:7SLpz2OuAX3cQQKzxnHQ5+sYy5roT9etJTa7EHxYraQ=
+github.com/cbeuw/connutil v0.0.0-20200407140739-52c0cf88d537/go.mod h1:6jR2SzckGv8hIIS9zWJ160mzGVVOYp4AXZMDtacL6LE=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/gorilla/mux v1.7.3 h1:gnP5JzjVOuiZD07fKKToCAOjS0yOpj/qPETTXCCS6hw=
 github.com/gorilla/mux v1.7.3/go.mod h1:1lud6UwP+6orDFRuTfBEV8e9/aOM/c4fVVCaMa2zaAs=
 github.com/gorilla/websocket v1.4.1 h1:q7AeDBpnBk8AogcD4DSag/Ukw/KV+YhzLj2bP5HvKCM=
 github.com/gorilla/websocket v1.4.1/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
-github.com/hashicorp/go-version v1.0.0 h1:21MVWPKDphxa7ineQQTrCU5brh7OuVVAzGOCnnCPtE8=
-github.com/hashicorp/go-version v1.0.0/go.mod h1:fltr4n8CU8Ke44wwGCBoEymUuxUHl09ZGVZPK5anwXA=
 github.com/juju/ratelimit v1.0.1 h1:+7AIFJVQ0EQgq/K9+0Krm7m530Du7tIz0METWzN0RgY=
 github.com/juju/ratelimit v1.0.1/go.mod h1:qapgC/Gy+xNh9UxzV13HGGl/6UXNN+ct+vwSgWNm/qk=
 github.com/konsorten/go-windows-terminal-sequences v1.0.1 h1:mweAR1A6xJ3oS2pRaGiHgQ4OO8tzTaLawm8vnODuwDk=
@@ -19,10 +19,6 @@ github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORN
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
-github.com/mitchellh/gox v1.0.1 h1:x0jD3dcHk9a9xPSDN6YEL4xL6Qz0dvNYm8yZqui5chI=
-github.com/mitchellh/gox v1.0.1/go.mod h1:ED6BioOGXMswlXa2zxfh/xdd5QhwYliBFn9V18Ap4z4=
-github.com/mitchellh/iochan v1.0.0 h1:C+X3KsSTLFVBr/tK1eYN/vs4rJcvsiLU338UhYPJWeY=
-github.com/mitchellh/iochan v1.0.0/go.mod h1:JwYml1nuB7xOzsp52dPpHFffvOCDupsG0QubkSMEySY=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/refraction-networking/utls v0.0.0-20190824032329-cc2996c81813 h1:fn33q5R1B4bgTSJXnxc7E6zR2bGMcxLaruMUt9thb5E=
diff --git a/internal/multiplex/blackhole_test.go b/internal/multiplex/blackhole_test.go
deleted file mode 100644
index 7d34215..0000000
--- a/internal/multiplex/blackhole_test.go
+++ /dev/null
@@ -1,41 +0,0 @@
-package multiplex
-
-import (
-	"bufio"
-	"io"
-	"io/ioutil"
-	"net"
-	"time"
-)
-
-type blackhole struct {
-	hole   *bufio.Writer
-	closer chan int
-}
-
-func newBlackHole() *blackhole {
-	return &blackhole{
-		hole:   bufio.NewWriter(ioutil.Discard),
-		closer: make(chan int),
-	}
-}
-func (b *blackhole) Read([]byte) (int, error) {
-	<-b.closer
-	return 0, io.EOF
-}
-func (b *blackhole) Write(in []byte) (int, error) { return b.hole.Write(in) }
-func (b *blackhole) Close() error {
-	b.closer <- 1
-	return nil
-}
-func (b *blackhole) LocalAddr() net.Addr {
-	ret, _ := net.ResolveTCPAddr("tcp", "127.0.0.1")
-	return ret
-}
-func (b *blackhole) RemoteAddr() net.Addr {
-	ret, _ := net.ResolveTCPAddr("tcp", "127.0.0.1")
-	return ret
-}
-func (b *blackhole) SetDeadline(t time.Time) error      { return nil }
-func (b *blackhole) SetReadDeadline(t time.Time) error  { return nil }
-func (b *blackhole) SetWriteDeadline(t time.Time) error { return nil }
diff --git a/internal/multiplex/stream_test.go b/internal/multiplex/stream_test.go
index 26d66f7..d917bee 100644
--- a/internal/multiplex/stream_test.go
+++ b/internal/multiplex/stream_test.go
@@ -7,6 +7,8 @@ import (
 	"net"
 	"testing"
 	"time"
+
+	"github.com/cbeuw/connutil"
 )
 
 func setupSesh(unordered bool) *Session {
@@ -25,7 +27,7 @@ func setupSesh(unordered bool) *Session {
 
 func BenchmarkStream_Write_Ordered(b *testing.B) {
 	const PAYLOAD_LEN = 1000
-	hole := newBlackHole()
+	hole := connutil.Discard()
 	sesh := setupSesh(false)
 	sesh.AddConnection(hole)
 	testData := make([]byte, PAYLOAD_LEN)
@@ -100,7 +102,7 @@ func BenchmarkStream_Read_Ordered(b *testing.B) {
 
 func TestStream_Write(t *testing.T) {
 	const PAYLOAD_LEN = 1000
-	hole := newBlackHole()
+	hole := connutil.Discard()
 	sesh := setupSesh(false)
 	sesh.AddConnection(hole)
 	testData := make([]byte, PAYLOAD_LEN)
@@ -128,11 +130,11 @@ func TestStream_Close(t *testing.T) {
 		testPayload,
 	}
 
-	conn, writingEnd := util.GetMockConn()
+	conn, writingEnd := connutil.AsyncPipe()
 	sesh.AddConnection(conn)
 	obfsBuf := make([]byte, 512)
 	i, _ := sesh.Obfs(f, obfsBuf)
-	writingEnd <- obfsBuf[:i]
+	writingEnd.Write(obfsBuf[:i])
 	time.Sleep(100 * time.Microsecond)
 	stream, err := sesh.Accept()
 	if err != nil {
@@ -163,7 +165,7 @@ func TestStream_Read(t *testing.T) {
 		testPayload,
 	}
 
-	conn, writingEnd := util.GetMockConn()
+	conn, writingEnd := connutil.AsyncPipe()
 	sesh.AddConnection(conn)
 
 	var streamID uint32
@@ -174,7 +176,7 @@ func TestStream_Read(t *testing.T) {
 		f.StreamID = streamID
 		i, _ := sesh.Obfs(f, obfsBuf)
 		streamID++
-		writingEnd <- obfsBuf[:i]
+		writingEnd.Write(obfsBuf[:i])
 		time.Sleep(100 * time.Microsecond)
 		stream, err := sesh.Accept()
 		if err != nil {
@@ -200,7 +202,7 @@ func TestStream_Read(t *testing.T) {
 		f.StreamID = streamID
 		i, _ := sesh.Obfs(f, obfsBuf)
 		streamID++
-		writingEnd <- obfsBuf[:i]
+		writingEnd.Write(obfsBuf[:i])
 		time.Sleep(100 * time.Microsecond)
 		stream, _ := sesh.Accept()
 		i, err := stream.Read(nil)
@@ -221,7 +223,7 @@ func TestStream_Read(t *testing.T) {
 		f.StreamID = streamID
 		i, _ := sesh.Obfs(f, obfsBuf)
 		streamID++
-		writingEnd <- obfsBuf[:i]
+		writingEnd.Write(obfsBuf[:i])
 		time.Sleep(100 * time.Microsecond)
 		stream, _ := sesh.Accept()
 		stream.Close()
@@ -246,7 +248,7 @@ func TestStream_Read(t *testing.T) {
 		f.StreamID = streamID
 		i, _ := sesh.Obfs(f, obfsBuf)
 		streamID++
-		writingEnd <- obfsBuf[:i]
+		writingEnd.Write(obfsBuf[:i])
 		time.Sleep(100 * time.Microsecond)
 		stream, _ := sesh.Accept()
 		sesh.Close()
@@ -282,7 +284,7 @@ func TestStream_UnorderedRead(t *testing.T) {
 		testPayload,
 	}
 
-	conn, writingEnd := util.GetMockConn()
+	conn, writingEnd := connutil.AsyncPipe()
 	sesh.AddConnection(conn)
 
 	var streamID uint32
@@ -293,7 +295,7 @@ func TestStream_UnorderedRead(t *testing.T) {
 		f.StreamID = streamID
 		i, _ := sesh.Obfs(f, obfsBuf)
 		streamID++
-		writingEnd <- obfsBuf[:i]
+		writingEnd.Write(obfsBuf[:i])
 		time.Sleep(100 * time.Microsecond)
 		stream, err := sesh.Accept()
 		if err != nil {
@@ -315,7 +317,7 @@ func TestStream_UnorderedRead(t *testing.T) {
 		f.StreamID = streamID
 		i, _ := sesh.Obfs(f, obfsBuf)
 		streamID++
-		writingEnd <- obfsBuf[:i]
+		writingEnd.Write(obfsBuf[:i])
 		time.Sleep(100 * time.Microsecond)
 		stream, _ := sesh.Accept()
 		i, err := stream.Read(nil)
@@ -336,7 +338,7 @@ func TestStream_UnorderedRead(t *testing.T) {
 		f.StreamID = streamID
 		i, _ := sesh.Obfs(f, obfsBuf)
 		streamID++
-		writingEnd <- obfsBuf[:i]
+		writingEnd.Write(obfsBuf[:i])
 		time.Sleep(100 * time.Microsecond)
 		stream, _ := sesh.Accept()
 		stream.Close()
@@ -361,7 +363,7 @@ func TestStream_UnorderedRead(t *testing.T) {
 		f.StreamID = streamID
 		i, _ := sesh.Obfs(f, obfsBuf)
 		streamID++
-		writingEnd <- obfsBuf[:i]
+		writingEnd.Write(obfsBuf[:i])
 		time.Sleep(100 * time.Microsecond)
 		stream, _ := sesh.Accept()
 		sesh.Close()
diff --git a/internal/multiplex/switchboard_test.go b/internal/multiplex/switchboard_test.go
index bfc2fa4..ba76b49 100644
--- a/internal/multiplex/switchboard_test.go
+++ b/internal/multiplex/switchboard_test.go
@@ -2,6 +2,7 @@ package multiplex
 
 import (
 	"github.com/cbeuw/Cloak/internal/util"
+	"github.com/cbeuw/connutil"
 	"math/rand"
 	"net"
 	"testing"
@@ -80,7 +81,7 @@ func TestSwitchboard_Send(t *testing.T) {
 }
 
 func BenchmarkSwitchboard_Send(b *testing.B) {
-	hole := newBlackHole()
+	hole := connutil.Discard()
 	seshConfig := &SessionConfig{
 		Obfuscator: nil,
 		Valve:      nil,
@@ -113,7 +114,7 @@ func TestSwitchboard_TxCredit(t *testing.T) {
 		UnitRead:   util.ReadTLS,
 	}
 	sesh := MakeSession(0, seshConfig)
-	hole := newBlackHole()
+	hole := connutil.Discard()
 	sesh.sb.addConn(hole)
 	connId, _, err := sesh.sb.pickRandConn()
 	if err != nil {
diff --git a/internal/server/websocketAux_test.go b/internal/server/websocketAux_test.go
index eb68c5a..b075ec7 100644
--- a/internal/server/websocketAux_test.go
+++ b/internal/server/websocketAux_test.go
@@ -2,12 +2,12 @@ package server
 
 import (
 	"bytes"
-	"github.com/cbeuw/Cloak/internal/util"
+	"github.com/cbeuw/connutil"
 	"testing"
 )
 
 func TestFirstBuffedConn_Read(t *testing.T) {
-	mockConn, writingEnd := util.GetMockConn()
+	mockConn, writingEnd := connutil.AsyncPipe()
 
 	expectedFirstPacket := []byte{1, 2, 3}
 	firstBuffedConn := &firstBuffedConn{
@@ -17,42 +17,42 @@ func TestFirstBuffedConn_Read(t *testing.T) {
 	}
 
 	buf := make([]byte, 1024)
-	n ,err :=firstBuffedConn.Read(buf)
+	n, err := firstBuffedConn.Read(buf)
 	if err != nil {
 		t.Error(err)
 		return
 	}
-	if !bytes.Equal(expectedFirstPacket, buf[:n]){
+	if !bytes.Equal(expectedFirstPacket, buf[:n]) {
 		t.Error("first read doesn't produce given packet")
 		return
 	}
 
-	expectedSecondPacket := []byte{4,5,6,7}
-	writingEnd <- expectedSecondPacket
-	n ,err =firstBuffedConn.Read(buf)
+	expectedSecondPacket := []byte{4, 5, 6, 7}
+	writingEnd.Write(expectedSecondPacket)
+	n, err = firstBuffedConn.Read(buf)
 	if err != nil {
 		t.Error(err)
 		return
 	}
-	if !bytes.Equal(expectedSecondPacket, buf[:n]){
+	if !bytes.Equal(expectedSecondPacket, buf[:n]) {
 		t.Error("second read doesn't produce subsequently written packet")
 		return
 	}
 }
 
-func TestWsAcceptor(t *testing.T){
-	mockConn, _ := util.GetMockConn()
+func TestWsAcceptor(t *testing.T) {
+	mockConn := connutil.Discard()
 	expectedFirstPacket := []byte{1, 2, 3}
 
-	wsAcceptor:=newWsAcceptor(mockConn, expectedFirstPacket)
-	_,err := wsAcceptor.Accept()
+	wsAcceptor := newWsAcceptor(mockConn, expectedFirstPacket)
+	_, err := wsAcceptor.Accept()
 	if err != nil {
 		t.Error(err)
 		return
 	}
 
-	_,err = wsAcceptor.Accept()
-	if err == nil{
+	_, err = wsAcceptor.Accept()
+	if err == nil {
 		t.Error("accepting second time doesn't return error")
 	}
-}
\ No newline at end of file
+}
diff --git a/internal/util/util.go b/internal/util/util.go
index bb33f49..4e0f362 100644
--- a/internal/util/util.go
+++ b/internal/util/util.go
@@ -6,7 +6,6 @@ import (
 	"crypto/rand"
 	"encoding/binary"
 	"errors"
-	"fmt"
 	"io"
 	"net"
 	"strconv"
@@ -137,21 +136,3 @@ func Pipe(dst net.Conn, src net.Conn, srcReadTimeout time.Duration) {
 		}
 	}
 }
-
-func GetMockConn() (net.Conn, chan []byte) {
-	ch := make(chan []byte)
-	l, _ := net.Listen("tcp", "127.0.0.1:0")
-	go func() {
-		conn, _ := net.Dial("tcp", l.Addr().String())
-		for {
-			data := <-ch
-			_, err := conn.Write(data)
-			if err != nil {
-				fmt.Println("cannot write to connection", err)
-			}
-		}
-	}()
-	conn, _ := l.Accept()
-
-	return conn, ch
-}