[3.15] gh-154289: Fix test_socket.testGetServBy on DragonFly (GH-154290) (GH-154294)

DragonFly lists "echo 4/ddp" before "echo 7/tcp" in /etc/services, like
FreeBSD, so avoid the "echo" service there too.
(cherry picked from commit 96059f9446510f594c4148d53bd1a4e3532af697)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

diff --git a/Lib/test/test_socket.py b/Lib/test/test_socket.py
index d831ba7565cf5f612f575c33d4148d00964f95c7..fd2e0a14e33d5215ab93eab55192dab2f192823c 100644 (file)
--- a/Lib/test/test_socket.py
+++ b/Lib/test/test_socket.py
@@ -1302,7 +1302,8 @@ class GeneralModuleTests(unittest.TestCase):
         # protocol, at least for modern Linuxes.
         if (
             sys.platform.startswith(
-                ('linux', 'android', 'freebsd', 'netbsd', 'gnukfreebsd'))
+                ('linux', 'android', 'freebsd', 'dragonfly', 'netbsd',
+                 'gnukfreebsd'))
             or is_apple
         ):
             # avoid the 'echo' service on this platform, as there is an