1 files changed, 9 insertions, 0 deletions
diff --git a/Lib/test/test_signal.py b/Lib/test/test_signal.py
index 2144d61..c2b5861 100644
--- a/Lib/test/test_signal.py
+++ b/Lib/test/test_signal.py
@@ -1,4 +1,5 @@
 import errno
+import inspect
 import os
 import random
 import signal
@@ -33,6 +34,14 @@ class GenericTests(unittest.TestCase):
                 self.assertIsInstance(sig, signal.Signals)
                 self.assertEqual(sys.platform, "win32")
 
+    def test_functions_module_attr(self):
+        # Issue #27718: If __all__ is not defined all non-builtin functions
+        # should have correct __module__ to be displayed by pydoc.
+        for name in dir(signal):
+            value = getattr(signal, name)
+            if inspect.isroutine(value) and not inspect.isbuiltin(value):
+                self.assertEqual(value.__module__, 'signal')
+
 
 @unittest.skipIf(sys.platform == "win32", "Not valid on Windows")
 class PosixTests(unittest.TestCase):