Issue #27275: Fixed implementation of pop() and popitem() methods in

subclasses of accelerated OrderedDict.

1 files changed, 59 insertions, 0 deletions

diff --git a/Lib/test/test_ordered_dict.py b/Lib/test/test_ordered_dict.py
index a35ed12..582ff56 100644
--- a/Lib/test/test_ordered_dict.py
+++ b/Lib/test/test_ordered_dict.py
@@ -775,5 +775,64 @@ class CPythonSubclassMappingTests(mapping_tests.BasicTestMappingProtocol):
         self.assertRaises(KeyError, d.popitem)
 
 
+class SimpleLRUCache:
+
+    def __init__(self, size):
+        super().__init__()
+        self.size = size
+
+    def __getitem__(self, item):
+        value = super().__getitem__(item)
+        self.move_to_end(item)
+        return value
+
+    def __setitem__(self, key, value):
+        while key not in self and len(self) >= self.size:
+            self.popitem(last=False)
+        super().__setitem__(key, value)
+        self.move_to_end(key)
+
+
+class SimpleLRUCacheTests:
+
+    def test_add_after_full(self):
+        c = self.type2test(2)
+        c['t1'] = 1
+        c['t2'] = 2
+        c['t3'] = 3
+        self.assertEqual(list(c), ['t2', 't3'])
+
+    def test_popitem(self):
+        c = self.type2test(3)
+        for i in range(1, 4):
+            c[i] = i
+        self.assertEqual(c.popitem(last=False), (1, 1))
+        self.assertEqual(c.popitem(last=True), (3, 3))
+
+    def test_change_order_on_get(self):
+        c = self.type2test(3)
+        for i in range(1, 4):
+            c[i] = i
+        self.assertEqual(list(c), list(range(1, 4)))
+        self.assertEqual(c[2], 2)
+        self.assertEqual(list(c), [1, 3, 2])
+
+
+class PySimpleLRUCacheTests(SimpleLRUCacheTests, unittest.TestCase):
+
+    class type2test(SimpleLRUCache, py_coll.OrderedDict):
+        pass
+
+
+@unittest.skipUnless(c_coll, 'requires the C version of the collections module')
+class CSimpleLRUCacheTests(SimpleLRUCacheTests, unittest.TestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        class type2test(SimpleLRUCache, c_coll.OrderedDict):
+            pass
+        cls.type2test = type2test
+
+
 if __name__ == "__main__":
     unittest.main()