From 3a9e1fda7ab30e04545d3eceea1f2ccd37fa1f15 Mon Sep 17 00:00:00 2001
From: Fantix King <fantix.king@gmail.com>
Date: Fri, 5 Aug 2022 04:45:36 -0400
Subject: [PATCH] gh-95573: Reduce test data size in test_asyncio/test_ssl.py
 (GH-95668)
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Co-authored-by: Łukasz Langa <lukasz@langa.pl>
---
 Lib/test/test_asyncio/test_ssl.py             | 19 ++++++++++++-------
 ...2-08-05-09-57-43.gh-issue-95573.edMdQB.rst |  6 ++++++
 2 files changed, 18 insertions(+), 7 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Tests/2022-08-05-09-57-43.gh-issue-95573.edMdQB.rst

diff --git a/Lib/test/test_asyncio/test_ssl.py b/Lib/test/test_asyncio/test_ssl.py
index a2b5f8d258c..5de9b7a14e8 100644
--- a/Lib/test/test_asyncio/test_ssl.py
+++ b/Lib/test/test_asyncio/test_ssl.py
@@ -5,6 +5,7 @@ import gc
 import logging
 import select
 import socket
+import sys
 import tempfile
 import threading
 import time
@@ -20,6 +21,10 @@ from test import support
 from test.test_asyncio import utils as test_utils
 
 
+MACOS = (sys.platform == 'darwin')
+BUF_MULTIPLIER = 1024 if not MACOS else 64
+
+
 def tearDownModule():
     asyncio.set_event_loop_policy(None)
 
@@ -191,8 +196,8 @@ class TestSSL(test_utils.TestCase):
         TOTAL_CNT = 25    # total number of clients that test will create
         TIMEOUT = support.LONG_TIMEOUT  # timeout for this test
 
-        A_DATA = b'A' * 1024 * 1024
-        B_DATA = b'B' * 1024 * 1024
+        A_DATA = b'A' * 1024 * BUF_MULTIPLIER
+        B_DATA = b'B' * 1024 * BUF_MULTIPLIER
 
         sslctx = self._create_server_ssl_context(
             test_utils.ONLYCERT, test_utils.ONLYKEY
@@ -287,8 +292,8 @@ class TestSSL(test_utils.TestCase):
         CNT = 0
         TOTAL_CNT = 25
 
-        A_DATA = b'A' * 1024 * 1024
-        B_DATA = b'B' * 1024 * 1024
+        A_DATA = b'A' * 1024 * BUF_MULTIPLIER
+        B_DATA = b'B' * 1024 * BUF_MULTIPLIER
 
         sslctx = self._create_server_ssl_context(
             test_utils.ONLYCERT,
@@ -1034,8 +1039,8 @@ class TestSSL(test_utils.TestCase):
         TOTAL_CNT = 25    # total number of clients that test will create
         TIMEOUT = support.LONG_TIMEOUT  # timeout for this test
 
-        A_DATA = b'A' * 1024 * 1024
-        B_DATA = b'B' * 1024 * 1024
+        A_DATA = b'A' * 1024 * BUF_MULTIPLIER
+        B_DATA = b'B' * 1024 * BUF_MULTIPLIER
 
         sslctx_1 = self._create_server_ssl_context(
             test_utils.ONLYCERT, test_utils.ONLYKEY)
@@ -1178,7 +1183,7 @@ class TestSSL(test_utils.TestCase):
         CNT = 0
         TOTAL_CNT = 25
 
-        A_DATA = b'A' * 1024 * 1024
+        A_DATA = b'A' * 1024 * BUF_MULTIPLIER
 
         sslctx = self._create_server_ssl_context(
             test_utils.ONLYCERT, test_utils.ONLYKEY)
diff --git a/Misc/NEWS.d/next/Tests/2022-08-05-09-57-43.gh-issue-95573.edMdQB.rst b/Misc/NEWS.d/next/Tests/2022-08-05-09-57-43.gh-issue-95573.edMdQB.rst
new file mode 100644
index 00000000000..8580556965e
--- /dev/null
+++ b/Misc/NEWS.d/next/Tests/2022-08-05-09-57-43.gh-issue-95573.edMdQB.rst
@@ -0,0 +1,6 @@
+:source:`Lib/test/test_asyncio/test_ssl.py` exposed a bug in the macOS
+kernel where intense concurrent load on non-blocking sockets occasionally
+causes :const:`errno.ENOBUFS` ("No buffer space available") to be emitted.
+FB11063974 filed with Apple, in the mean time as a workaround buffer size
+used in tests on macOS is decreased to avoid intermittent failures.  Patch
+by Fantix King.