bpo-42641: Enhance test_select.test_select() (GH-23782)
Enhance test_select.test_select(): it now takes 500 ms rather than 10
seconds.
* Use Python rather than a shell as the child process to make the
test more portable.
* Use a sleep of 50 ms per line rather than 1 second.
* Use subprocess.Popen rather than os.popen().
diff --git a/Lib/test/test_select.py b/Lib/test/test_select.py
index 458998a..4ddd5fb 100644
--- a/Lib/test/test_select.py
+++ b/Lib/test/test_select.py
@@ -1,7 +1,9 @@
import errno
import os
import select
+import subprocess
import sys
+import textwrap
import unittest
from test import support
@@ -45,16 +47,25 @@ def test_returned_list_identity(self):
self.assertIsNot(w, x)
def test_select(self):
- cmd = 'for i in 0 1 2 3 4 5 6 7 8 9; do echo testing...; sleep 1; done'
- with os.popen(cmd) as p:
- for tout in (0, 1, 2, 4, 8, 16) + (None,)*10:
+ code = textwrap.dedent('''
+ import time
+ for i in range(10):
+ print("testing...", flush=True)
+ time.sleep(0.050)
+ ''')
+ cmd = [sys.executable, '-I', '-c', code]
+ with subprocess.Popen(cmd, stdout=subprocess.PIPE) as proc:
+ pipe = proc.stdout
+ for timeout in (0, 1, 2, 4, 8, 16) + (None,)*10:
if support.verbose:
- print('timeout =', tout)
- rfd, wfd, xfd = select.select([p], [], [], tout)
- if (rfd, wfd, xfd) == ([], [], []):
+ print(f'timeout = {timeout}')
+ rfd, wfd, xfd = select.select([pipe], [], [], timeout)
+ self.assertEqual(wfd, [])
+ self.assertEqual(xfd, [])
+ if not rfd:
continue
- if (rfd, wfd, xfd) == ([p], [], []):
- line = p.readline()
+ if rfd == [pipe]:
+ line = pipe.readline()
if support.verbose:
print(repr(line))
if not line:
@@ -62,7 +73,8 @@ def test_select(self):
print('EOF')
break
continue
- self.fail('Unexpected return values from select():', rfd, wfd, xfd)
+ self.fail('Unexpected return values from select():',
+ rfd, wfd, xfd)
# Issue 16230: Crash on select resized list
def test_select_mutated(self):