Refactor bufReader to use BytesPipe

Signed-off-by: Alexander Morozov <lk4d4@docker.com>

ioutils/readers_test.go

@@ -7,6 +7,7 @@ import (
 	"io/ioutil"
 	"strings"
 	"testing"
+	"time"
 )
 
 // Implement io.Reader
@@ -61,8 +62,8 @@ func TestNewBufReaderWithDrainbufAndBuffer(t *testing.T) {
 	reader, writer := io.Pipe()
 
 	drainBuffer := make([]byte, 1024)
-	buffer := bytes.Buffer{}
-	bufreader := NewBufReaderWithDrainbufAndBuffer(reader, drainBuffer, &buffer)
+	buffer := NewBytesPipe(nil)
+	bufreader := NewBufReaderWithDrainbufAndBuffer(reader, drainBuffer, buffer)
 
 	// Write everything down to a Pipe
 	// Usually, a pipe should block but because of the buffered reader,
@@ -76,7 +77,11 @@ func TestNewBufReaderWithDrainbufAndBuffer(t *testing.T) {
 
 	// Drain the reader *after* everything has been written, just to verify
 	// it is indeed buffering
-	<-done
+	select {
+	case <-done:
+	case <-time.After(1 * time.Second):
+		t.Fatal("timeout")
+	}
 
 	output, err := ioutil.ReadAll(bufreader)
 	if err != nil {