test: try mitigating port clashes

Also, I don't think calling random.seed is necessary.

1 files changed, 21 insertions, 0 deletions

diff --git a/test/py/lib/net.py b/test/py/lib/net.py
new file mode 100644
index 0000000..816dd99
--- /dev/null
+++ b/test/py/lib/net.py
@@ -0,0 +1,21 @@
+# Copyright (c) 2023 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is part of the "cimple" project.
+# For details, see https://github.com/egor-tensin/cimple.
+# Distributed under the MIT License.
+
+from contextlib import closing
+import random
+import socket
+
+
+def port_is_open(host, port):
+    with closing(socket.socket(socket.AF_INET, socket.SOCK_STREAM)) as sock:
+        return sock.connect_ex((host, port)) == 0
+
+
+def random_unused_port():
+    while True:
+        port = random.randint(20000, 40000)
+        if port_is_open('127.0.0.1', port):
+            continue
+        return port