2 files changed, 19 insertions, 5 deletions
diff --git a/Lib/test/test_devpoll.py b/Lib/test/test_devpoll.py
index bef4e18..c7bacf8 100644
--- a/Lib/test/test_devpoll.py
+++ b/Lib/test/test_devpoll.py
@@ -87,6 +87,17 @@ class DevPollTests(unittest.TestCase):
         self.assertRaises(OverflowError, pollster.poll, 1 << 63)
         self.assertRaises(OverflowError, pollster.poll, 1 << 64)
 
+    def test_events_mask_overflow(self):
+        pollster = select.devpoll()
+        w, r = os.pipe()
+        pollster.register(w)
+        # Issue #17919
+        self.assertRaises(OverflowError, pollster.register, 0, -1)
+        self.assertRaises(OverflowError, pollster.register, 0, USHRT_MAX + 1)
+        self.assertRaises(OverflowError, pollster.modify, 1, -1)
+        self.assertRaises(OverflowError, pollster.modify, 1, USHRT_MAX + 1)
+
+
 def test_main():
     run_unittest(DevPollTests)
 
diff --git a/Lib/test/test_poll.py b/Lib/test/test_poll.py
index e51e6f0..3c86ef6 100644
--- a/Lib/test/test_poll.py
+++ b/Lib/test/test_poll.py
@@ -3,7 +3,7 @@
 import os
 import random
 import select
-import _testcapi
+from _testcapi import USHRT_MAX, INT_MAX, UINT_MAX
 try:
     import threading
 except ImportError:
@@ -159,10 +159,13 @@ class PollTests(unittest.TestCase):
         if x != 5:
             self.fail('Overflow must have occurred')
 
-        pollster = select.poll()
-        # Issue 15989
-        self.assertRaises(OverflowError, pollster.poll, _testcapi.INT_MAX + 1)
-        self.assertRaises(OverflowError, pollster.poll, _testcapi.UINT_MAX + 1)
+        # Issues #15989, #17919
+        self.assertRaises(OverflowError, pollster.register, 0, -1)
+        self.assertRaises(OverflowError, pollster.register, 0, USHRT_MAX + 1)
+        self.assertRaises(OverflowError, pollster.modify, 1, -1)
+        self.assertRaises(OverflowError, pollster.modify, 1, USHRT_MAX + 1)
+        self.assertRaises(OverflowError, pollster.poll, INT_MAX + 1)
+        self.assertRaises(OverflowError, pollster.poll, UINT_MAX + 1)
 
     @unittest.skipUnless(threading, 'Threading required for this test.')
     @reap_threads