diff --git a/src/vmm/src/devices/virtio/net/tap.rs b/src/vmm/src/devices/virtio/net/tap.rs
index 40a8491ffad..3cfdf1e7fdf 100644
--- a/src/vmm/src/devices/virtio/net/tap.rs
+++ b/src/vmm/src/devices/virtio/net/tap.rs
@@ -306,7 +306,8 @@ pub mod tests {
             fragment3.as_slice(),
         ]);
 
-        tap.write_iovec(&scattered).unwrap();
+        let num_bytes = tap.write_iovec(&scattered).unwrap();
+        assert_eq!(num_bytes, scattered.len() as usize);
 
         let mut read_buf = vec![0u8; scattered.len() as usize];
         assert!(tap_traffic_simulator.pop_rx_packet(&mut read_buf));