Instantiate the OS-related exception as soon as we raise it, so that

"except" works properly.

1 files changed, 12 insertions, 0 deletions

diff --git a/Lib/test/test_pep3151.py b/Lib/test/test_pep3151.py
index 9d92425..3c52bc6 100644
--- a/Lib/test/test_pep3151.py
+++ b/Lib/test/test_pep3151.py
@@ -79,6 +79,18 @@ class HierarchyTest(unittest.TestCase):
         e = SubOSError(EEXIST, "Bad file descriptor")
         self.assertIs(type(e), SubOSError)
 
+    def test_try_except(self):
+        # This checks that try .. except checks the concrete exception
+        # (FileNotFoundError) and not the base type specified when
+        # PyErr_SetFromErrnoWithFilenameObject was called.
+        # (it is therefore deliberate that it doesn't use assertRaises)
+        try:
+            open("some_hopefully_non_existing_file")
+        except FileNotFoundError:
+            pass
+        else:
+            self.fail("should have raised a FileNotFoundError")
+
 
 class AttributesTest(unittest.TestCase):