1 files changed, 35 insertions, 0 deletions
diff --git a/Lib/test/test_array.py b/Lib/test/test_array.py
index 7ae34a99a9..3dd4f6df3b 100755
--- a/Lib/test/test_array.py
+++ b/Lib/test/test_array.py
@@ -272,6 +272,12 @@ class BaseTest(unittest.TestCase):
             a,
             array.array(self.typecode, self.example[::-1]+2*self.example)
         )
+        a = array.array(self.typecode, self.example)
+        a += a
+        self.assertEqual(
+            a,
+            array.array(self.typecode, self.example + self.example)
+        )
 
         b = array.array(self.badtypecode())
         self.assertRaises(TypeError, a.__add__, b)
@@ -667,6 +673,13 @@ class BaseTest(unittest.TestCase):
             array.array(self.typecode, self.example+self.example[::-1])
         )
 
+        a = array.array(self.typecode, self.example)
+        a.extend(a)
+        self.assertEqual(
+            a,
+            array.array(self.typecode, self.example+self.example)
+        )
+
         b = array.array(self.badtypecode())
         self.assertRaises(TypeError, a.extend, b)
 
@@ -749,9 +762,31 @@ class BaseTest(unittest.TestCase):
         ArraySubclassWithKwargs('b', newarg=1)
 
     def test_create_from_bytes(self):
+        # XXX This test probably needs to be moved in a subclass or
+        # generalized to use self.typecode.
         a = array.array('H', b"1234")
         self.assertEqual(len(a) * a.itemsize, 4)
 
+    def test_memoryview_no_resize(self):
+        # Test for issue 4509.
+        a = array.array(self.typecode, self.example)
+        m = memoryview(a)
+        expected = m.tobytes()
+        self.assertRaises(BufferError, a.pop, 0)
+        self.assertEqual(m.tobytes(), expected)
+        self.assertRaises(BufferError, a.remove, a[0])
+        self.assertEqual(m.tobytes(), expected)
+        self.assertRaises(BufferError, a.__setitem__, slice(0, 0), a)
+        self.assertEqual(m.tobytes(), expected)
+        self.assertRaises(BufferError, a.__delitem__, slice(0, len(a)))
+        self.assertEqual(m.tobytes(), expected)
+        self.assertRaises(BufferError, a.__imul__, 2)
+        self.assertEqual(m.tobytes(), expected)
+        self.assertRaises(BufferError, a.__iadd__, a)
+        self.assertEqual(m.tobytes(), expected)
+        self.assertRaises(BufferError, a.extend, a)
+        self.assertEqual(m.tobytes(), expected)
+
 
 class StringTest(BaseTest):