Merge pull request #27 from m-lab/replace-tcpconn-with-interface

Replace *net.TCPConn with a TCPLikeConn abstraction

internal/handler/handler_test.go

@@ -42,7 +42,7 @@ func setupTestWSDialer(u *url.URL) *websocket.Dialer {
 			if err != nil {
 				return nil, err
 			}
-			return netx.FromTCPConn(conn.(*net.TCPConn))
+			return netx.FromTCPLikeConn(conn.(*net.TCPConn))
 		},
 	}
 }

internal/netx/conn.go

@@ -33,6 +33,13 @@ type ConnInfo interface {
 	SaveUUID(context.Context) context.Context
 }
 
+// TCPLikeConn is a net.Conn with a File() method. This is useful for creating a
+// netx.Conn based on a custom TCPConn-like type - e.g. for testing.
+type TCPLikeConn interface {
+	net.Conn
+	File() (*os.File, error)
+}
+
 // ToConnInfo is a helper function to convert a net.Conn into a netx.ConnInfo.
 // It panics if netConn does not contain a type supporting ConnInfo.
 func ToConnInfo(netConn net.Conn) ConnInfo {
@@ -57,8 +64,9 @@ type Conn struct {
 	bytesWritten atomic.Uint64
 }
 
-func FromTCPConn(tcpConn *net.TCPConn) (*Conn, error) {
-	return fromTCPConn(tcpConn)
+// FromTCPLikeConn creates a netx.Conn from a TCPLikeConn.
+func FromTCPLikeConn(tcpConn TCPLikeConn) (*Conn, error) {
+	return fromTCPLikeConn(tcpConn)
 }
 
 // Read reads from the underlying net.Conn and updates the read bytes counter.

internal/netx/conn_linux.go

@@ -1,11 +1,10 @@
 package netx
 
 import (
-	"net"
 	"time"
 )
 
-func fromTCPConn(tcpConn *net.TCPConn) (*Conn, error) {
+func fromTCPLikeConn(tcpConn TCPLikeConn) (*Conn, error) {
 	// On Linux system, this can only fail when the file duplication fails.
 	fp, err := tcpConn.File()
 	if err != nil {

internal/netx/conn_stub.go

@@ -4,11 +4,10 @@
 package netx
 
 import (
-	"net"
 	"time"
 )
 
-func fromTCPConn(tcpConn *net.TCPConn) (*Conn, error) {
+func fromTCPLikeConn(tcpConn TCPLikeConn) (*Conn, error) {
 	// On non-Linux systems, TCPInfo/BBRInfo aren't supported, the file pointer
 	// is not needed.
 	return &Conn{

internal/netx/listener_stub.go

@@ -11,5 +11,5 @@ func (ln *Listener) accept() (net.Conn, error) {
 		return nil, err
 	}
 
-	return fromTCPConn(tc)
+	return fromTCPLikeConn(tc)
 }

pkg/throughput1/protocol_test.go

@@ -106,7 +106,7 @@ func TestProtocol_Download(t *testing.T) {
 			if err != nil {
 				return nil, err
 			}
-			return netx.FromTCPConn(conn.(*net.TCPConn))
+			return netx.FromTCPLikeConn(conn.(*net.TCPConn))
 		},
 	}