Check netem cmd sucess and pytest-timeout pkg existence

hw/1_tcp/conftest.py

@@ -0,0 +1,15 @@
+import pytest
+import pkgutil
+
+def pytest_configure(config):
+    found_pytest_timeout = False
+    for pkg in pkgutil.iter_modules():
+        if pkg.name == "pytest_timeout":
+             found_pytest_timeout = True
+             break
+    if not found_pytest_timeout:
+        pytest.exit(
+            "pytest-timeout not found. Please install it via package manager " +
+            "(usually, package name is python3-pytest-timeout) or pip " +
+            "(sudo pip install python3-pytest-timeout)."
+        )

hw/1_tcp/protocol_test.py

@@ -1,6 +1,7 @@
 import os
 import random
 from contextlib import closing
+import platform
 
 import pytest
 from testable_thread import TestableThread
@@ -44,7 +45,6 @@ def run_test(client_class, server_class, iterations, msg_size=None):
 
 current_netem_state = None
 
-
 def setup_netem(packet_loss, duplicate, reorder):
     global current_netem_state
     if current_netem_state == (packet_loss, duplicate, reorder):
@@ -54,8 +54,16 @@ def setup_netem(packet_loss, duplicate, reorder):
     if reorder > 0:
         netem_cmd += f" reorder {100 - reorder}%"
     netem_cmd += " delay 10ms rate 1Mbit"
-    os.system(netem_cmd)
-
+    return_code = os.system(netem_cmd)
+    if return_code != 0:
+        message = "Could not configure netem. Please check tc executable is available."
+        if platform.system() != "Linux":
+            message = (
+                "Linux is needed in order to execute tests. " +
+                "If docker is available, you can use it."
+            )
+        # Also exits even if not under pytest.
+        pytest.exit(message)
 
 @pytest.mark.parametrize("iterations", [10, 50, 100])
 @pytest.mark.timeout(30)

hw/1_tcp/test.sh

@@ -1,4 +1,4 @@
 #!/usr/bin/env bash
 set -xeuo pipefail
 
-pytest -v protocol_test.py -o log_cli=true --durations=0
+pytest -v protocol_test.py -o log_cli=true --durations=0 --capture=sys