From cc52e02c96e9e26d59c6512f18516657e353cbe1 Mon Sep 17 00:00:00 2001
From: Nick Pope <nick@nickpope.me.uk>
Date: Sat, 23 Jul 2022 13:18:04 +0100
Subject: [PATCH] Refs #32948 -- Added more tests for django.utils.tree.Node.

The tests for creating new instances or copying instances of Node and
its subclasses didn't fully capture the behaviour of the implementation,
particularly around whether the `children` list or is contents were the
same as the source.
---
 tests/utils_tests/test_tree.py | 42 ++++++++++++++++++++++++++++++----
 1 file changed, 38 insertions(+), 4 deletions(-)

diff --git a/tests/utils_tests/test_tree.py b/tests/utils_tests/test_tree.py
index fcc4c3147d..81002e68c9 100644
--- a/tests/utils_tests/test_tree.py
+++ b/tests/utils_tests/test_tree.py
@@ -69,11 +69,45 @@ class NodeTests(unittest.TestCase):
         self.node1.negate()
         self.assertFalse(self.node1.negated)
 
+    def test_new_instance(self):
+        SubNode = type("SubNode", (Node,), {})
+
+        a = SubNode([SubNode(["a", "b"], OR), "c"], AND)
+        b = SubNode._new_instance(a.children, a.connector, a.negated)
+        self.assertEqual(a, b)
+        # Children lists are the same object, but equal.
+        self.assertIsNot(a.children, b.children)
+        self.assertEqual(a.children, b.children)
+        # Child Node objects are the same objects.
+        for a_child, b_child in zip(a.children, b.children):
+            if isinstance(a_child, Node):
+                self.assertIs(a_child, b_child)
+            self.assertEqual(a_child, b_child)
+
+    def test_copy(self):
+        a = Node([Node(["a", "b"], OR), "c"], AND)
+        b = copy.copy(a)
+        self.assertEqual(a, b)
+        # Children lists are the same object.
+        self.assertIs(a.children, b.children)
+        # Child Node objects are the same objects.
+        for a_child, b_child in zip(a.children, b.children):
+            if isinstance(a_child, Node):
+                self.assertIs(a_child, b_child)
+            self.assertEqual(a_child, b_child)
+
     def test_deepcopy(self):
-        node4 = copy.copy(self.node1)
-        node5 = copy.deepcopy(self.node1)
-        self.assertIs(self.node1.children, node4.children)
-        self.assertIsNot(self.node1.children, node5.children)
+        a = Node([Node(["a", "b"], OR), "c"], AND)
+        b = copy.deepcopy(a)
+        self.assertEqual(a, b)
+        # Children lists are not be the same object, but equal.
+        self.assertIsNot(a.children, b.children)
+        self.assertEqual(a.children, b.children)
+        # Child Node objects are not be the same objects.
+        for a_child, b_child in zip(a.children, b.children):
+            if isinstance(a_child, Node):
+                self.assertIsNot(a_child, b_child)
+            self.assertEqual(a_child, b_child)
 
     def test_eq_children(self):
         node = Node(self.node1_children)