diff --git a/util/error.go b/util/error.go
index 93f212e..ebed6a8 100644
--- a/util/error.go
+++ b/util/error.go
@@ -94,3 +94,13 @@ func (err *Err) Error() string {
 	}
 	return msg
 }
+
+// HasErrCode returns true if err is an *Err and err.Code == code.
+func HasErrCode(err error, code ErrCode) bool {
+	switch err := err.(type) {
+	case *Err:
+		return err.Code == code
+	default:
+		return false
+	}
+}
diff --git a/wire/scanner_test.go b/wire/scanner_test.go
index 20b402b..6226404 100644
--- a/wire/scanner_test.go
+++ b/wire/scanner_test.go
@@ -7,6 +7,7 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/zach-klippenstein/goadb/util"
 )
 
 func TestReadStatusOkay(t *testing.T) {
@@ -20,7 +21,7 @@ func TestReadStatusOkay(t *testing.T) {
 func TestReadIncompleteStatus(t *testing.T) {
 	s := NewScannerString("oka")
 	_, err := s.ReadStatus()
-	assert.Equal(t, incompleteMessage("status", 3, 4), err)
+	assert.Equal(t, errIncompleteMessage("status", 3, 4), err)
 	assertEof(t, s)
 }
 
@@ -35,7 +36,7 @@ func TestReadLength(t *testing.T) {
 func TestReadIncompleteLength(t *testing.T) {
 	s := NewScannerString("aaa")
 	_, err := s.readLength()
-	assert.Equal(t, incompleteMessage("length", 3, 4), err)
+	assert.Equal(t, errIncompleteMessage("length", 3, 4), err)
 	assertEof(t, s)
 }
 
@@ -78,7 +79,7 @@ func TestReadIncompleteMessage(t *testing.T) {
 	s := NewScannerString("0005hel")
 	msg, err := ReadMessageString(s)
 	assert.Error(t, err)
-	assert.Equal(t, incompleteMessage("message data", 3, 5), err)
+	assert.Equal(t, errIncompleteMessage("message data", 3, 5), err)
 	assert.Equal(t, "hel\000\000", msg)
 	assertEof(t, s)
 }
@@ -97,7 +98,7 @@ func NewEofBuffer(str string) *TestReader {
 
 func assertEof(t *testing.T, s *realScanner) {
 	msg, err := s.ReadMessage()
-	assert.Equal(t, io.EOF, err)
+	assert.True(t, util.HasErrCode(err, util.NetworkError))
 	assert.Nil(t, msg)
 }
 
diff --git a/wire/sync_test.go b/wire/sync_test.go
index d11a522..1966d55 100644
--- a/wire/sync_test.go
+++ b/wire/sync_test.go
@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/zach-klippenstein/goadb/util"
 )
 
 var (
@@ -35,7 +36,7 @@ func TestSyncSendOctetStringTooLong(t *testing.T) {
 	var buf bytes.Buffer
 	s := NewSyncSender(&buf)
 	err := s.SendOctetString("hello")
-	assert.EqualError(t, err, "octet string must be exactly 4 bytes: 'hello'")
+	assert.Equal(t, util.AssertionErrorf("octet string must be exactly 4 bytes: 'hello'"), err)
 }
 
 func TestSyncReadTime(t *testing.T) {
@@ -63,7 +64,7 @@ func TestSyncReadString(t *testing.T) {
 func TestSyncReadStringTooShort(t *testing.T) {
 	s := NewSyncScanner(strings.NewReader("\005\000\000\000h"))
 	_, err := s.ReadString()
-	assert.EqualError(t, err, "incomplete bytes: read 1 bytes, expecting 5")
+	assert.Equal(t, errIncompleteMessage("bytes", 1, 5), err)
 }
 
 func TestSyncSendString(t *testing.T) {