fix(test): add sleep to wait for socat spinup in test_tap_offload

We are seeing an intermittent failure of the form

FAILED test_net.py::test_tap_offload - ChildProcessError:
[17861] Command:['ssh', ..., 'sync; cat /tmp/out.txt']
[17861] stdout:
[17861] stderr:
cat: /tmp/out.txt: No such file or directory

It seems this is due to not waiting long enough for socat to spin up, so
add a quick sleep which makes the issue disappear.

Signed-off-by: Patrick Roy <[email protected]>

Author: roypat

tests/integration_tests/functional/test_net.py

@@ -111,6 +111,9 @@ def test_tap_offload(uvm_any):
         f"nohup socat UDP4-LISTEN:{port} OPEN:{out_filename},creat > /dev/null 2>&1 &"
     )
 
+    # wait for socat server to spin up
+    time.sleep(1)
+
     # Try to send a UDP message from host with UDP offload enabled
     vm.netns.check_output(f"python3 ./host_tools/udp_offload.py {vm.ssh.host} {port}")