diff --git a/metropolis/test/nanoswitch/socks.go b/metropolis/test/nanoswitch/socks.go
index a85e9a3..b8e7107 100644
--- a/metropolis/test/nanoswitch/socks.go
+++ b/metropolis/test/nanoswitch/socks.go
@@ -64,7 +64,7 @@
 func runSOCKSProxy(ctx context.Context) error {
 	lis, err := net.Listen("tcp", fmt.Sprintf(":%d", SOCKSPort))
 	if err != nil {
-		return fmt.Errorf("failed to listen on :%d : %v", SOCKSPort, err)
+		return fmt.Errorf("failed to listen on :%d : %w", SOCKSPort, err)
 	}
 
 	h := &socksHandler{}