bpo-39259: poplib now rejects timeout = 0 (GH-17912)

poplib.POP3 and poplib.POP3_SSL now raise a ValueError
if the given timeout for their constructor is zero to
prevent the creation of a non-blocking socket.

1 files changed, 7 insertions, 5 deletions

diff --git a/Lib/test/test_poplib.py b/Lib/test/test_poplib.py
index 911cba1..7f06d19 100644
--- a/Lib/test/test_poplib.py
+++ b/Lib/test/test_poplib.py
@@ -481,7 +481,7 @@ class TestTimeouts(TestCase):
         self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
         self.sock.settimeout(60)  # Safety net. Look issue 11812
         self.port = test_support.bind_port(self.sock)
-        self.thread = threading.Thread(target=self.server, args=(self.evt,self.sock))
+        self.thread = threading.Thread(target=self.server, args=(self.evt, self.sock))
         self.thread.daemon = True
         self.thread.start()
         self.evt.wait()
@@ -505,12 +505,12 @@ class TestTimeouts(TestCase):
 
     def testTimeoutDefault(self):
         self.assertIsNone(socket.getdefaulttimeout())
-        socket.setdefaulttimeout(30)
+        socket.setdefaulttimeout(test_support.LOOPBACK_TIMEOUT)
         try:
             pop = poplib.POP3(HOST, self.port)
         finally:
             socket.setdefaulttimeout(None)
-        self.assertEqual(pop.sock.gettimeout(), 30)
+        self.assertEqual(pop.sock.gettimeout(), test_support.LOOPBACK_TIMEOUT)
         pop.close()
 
     def testTimeoutNone(self):
@@ -524,9 +524,11 @@ class TestTimeouts(TestCase):
         pop.close()
 
     def testTimeoutValue(self):
-        pop = poplib.POP3(HOST, self.port, timeout=30)
-        self.assertEqual(pop.sock.gettimeout(), 30)
+        pop = poplib.POP3(HOST, self.port, timeout=test_support.LOOPBACK_TIMEOUT)
+        self.assertEqual(pop.sock.gettimeout(), test_support.LOOPBACK_TIMEOUT)
         pop.close()
+        with self.assertRaises(ValueError):
+            poplib.POP3(HOST, self.port, timeout=0)
 
 
 def test_main():