bpo-33773: Fix test.support.fd_count() on Linux/FreBSD (GH-7421) (GH-7456)
Substract one because listdir() opens internally a file
descriptor to list the content of the /proc/self/fd/ directory.
Add test_support.test_fd_count().
Move also MAXFD code before msvcrt.CrtSetReportMode(), to make sure
that the report mode is always restored on failure.
(cherry picked from commit 492d6424a7ca907c8ec1df21e51062e8f3d88e32)
diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
index f67c0da..6da2597 100644
--- a/Lib/test/support/__init__.py
+++ b/Lib/test/support/__init__.py
@@ -2068,11 +2068,20 @@
if sys.platform.startswith(('linux', 'freebsd')):
try:
names = os.listdir("/proc/self/fd")
- return len(names)
+ # Substract one because listdir() opens internally a file
+ # descriptor to list the content of the /proc/self/fd/ directory.
+ return len(names) - 1
except OSError as exc:
if exc.errno != errno.ENOENT:
raise
+ MAXFD = 256
+ if hasattr(os, 'sysconf'):
+ try:
+ MAXFD = os.sysconf("SC_OPEN_MAX")
+ except OSError:
+ pass
+
old_modes = None
if sys.platform == 'win32':
# bpo-25306, bpo-31009: Call CrtSetReportMode() to not kill the process
@@ -2090,13 +2099,6 @@
msvcrt.CRT_ASSERT):
old_modes[report_type] = msvcrt.CrtSetReportMode(report_type, 0)
- MAXFD = 256
- if hasattr(os, 'sysconf'):
- try:
- MAXFD = os.sysconf("SC_OPEN_MAX")
- except OSError:
- pass
-
try:
count = 0
for fd in range(MAXFD):
diff --git a/Lib/test/test_test_support.py b/Lib/test/test_test_support.py
index 421a9ef..60476b7 100644
--- a/Lib/test/test_test_support.py
+++ b/Lib/test/test_test_support.py
@@ -417,6 +417,17 @@
self.assertTrue(support.match_test(test_access))
self.assertFalse(support.match_test(test_chdir))
+ def test_fd_count(self):
+ # We cannot test the absolute value of fd_count(): on old Linux
+ # kernel or glibc versions, os.urandom() keeps a FD open on
+ # /dev/urandom device and Python has 4 FD opens instead of 3.
+ start = support.fd_count()
+ fd = os.open(__file__, os.O_RDONLY)
+ try:
+ more = support.fd_count()
+ finally:
+ os.close(fd)
+ self.assertEqual(more - start, 1)
# XXX -follows a list of untested API
# make_legacy_pyc