From b3520030f57b050914a14f4363e3dccff3e51163 Mon Sep 17 00:00:00 2001
From: Benjamin Dauvergne <bdauvergne@entrouvert.com>
Date: Wed, 21 Dec 2022 16:07:21 +0100
Subject: [PATCH] tests: improve search of a free TCP port (#72645)

---
 hobo/test_utils.py   | 12 ++++++++++++
 tests/test_emails.py |  9 ++-------
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/hobo/test_utils.py b/hobo/test_utils.py
index 47bd38d..2aa8947 100644
--- a/hobo/test_utils.py
+++ b/hobo/test_utils.py
@@ -16,6 +16,9 @@
 
 import hashlib
 import os
+import socket
+import struct
+from contextlib import closing
 
 
 def get_safe_db_name(max_length=53):
@@ -47,3 +50,12 @@ def get_safe_db_name(max_length=53):
     truncated_db_name = full_db_name[:prefix_length] + '_' + hashcode + '_' + full_db_name[-suffix_length:]
     assert len(truncated_db_name) == max_length
     return truncated_db_name
+
+
+def find_free_port():
+    with closing(socket.socket(socket.AF_INET, socket.SOCK_STREAM)) as s:
+        s.bind(('', 0))
+        # SO_LINGER (man 7 socket) l_onoff=1 l_linger=0, immediately release
+        # the port on closing of the socket
+        s.setsockopt(socket.SOL_SOCKET, socket.SO_LINGER, struct.pack("ii", 1, 0))
+        return s.getsockname()[1]
diff --git a/tests/test_emails.py b/tests/test_emails.py
index 47f601e..779641b 100644
--- a/tests/test_emails.py
+++ b/tests/test_emails.py
@@ -16,17 +16,12 @@ from test_manager import login
 
 from hobo.emails.validators import validate_email_address
 from hobo.environment.models import Variable
+from hobo.test_utils import find_free_port
 
 
 @pytest.fixture
 def port_available():
-    errno = 0
-    while not errno:
-        port = random.randint(49152, 65534)
-        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-        errno = sock.connect_ex(('127.0.0.1', port))
-        sock.close()
-    return port
+    return find_free_port()
 
 
 @pytest.fixture