bpo-30486: Allow setting cell value (#1840)

The cell_contents attribute of the cell object is now writable.

1 files changed, 20 insertions, 0 deletions

diff --git a/Lib/test/test_funcattrs.py b/Lib/test/test_funcattrs.py
index 8f481bb..35fd657 100644
--- a/Lib/test/test_funcattrs.py
+++ b/Lib/test/test_funcattrs.py
@@ -93,6 +93,26 @@ class FunctionPropertiesTest(FuncAttrsTest):
             self.fail("shouldn't be able to read an empty cell")
         a = 12
 
+    def test_set_cell(self):
+        a = 12
+        def f(): return a
+        c = f.__closure__
+        c[0].cell_contents = 9
+        self.assertEqual(c[0].cell_contents, 9)
+        self.assertEqual(f(), 9)
+        self.assertEqual(a, 9)
+        del c[0].cell_contents
+        try:
+            c[0].cell_contents
+        except ValueError:
+            pass
+        else:
+            self.fail("shouldn't be able to read an empty cell")
+        with self.assertRaises(NameError):
+            f()
+        with self.assertRaises(UnboundLocalError):
+            print(a)
+
     def test___name__(self):
         self.assertEqual(self.b.__name__, 'b')
         self.b.__name__ = 'c'