bpo-36543: Revert "bpo-36543: Remove the xml.etree.cElementTree module." (GH-20117)

* Revert "bpo-36543: Remove the xml.etree.cElementTree module. (GH-19108)"

This reverts commit b33e52511a59c6da7132c226b7f7489b092a33eb.

2 files changed, 18 insertions, 0 deletions

diff --git a/Lib/test/test_xml_etree_c.py b/Lib/test/test_xml_etree_c.py
index 7437e13..e26e171 100644
--- a/Lib/test/test_xml_etree_c.py
+++ b/Lib/test/test_xml_etree_c.py
@@ -8,6 +8,9 @@ import unittest
 
 cET = import_fresh_module('xml.etree.ElementTree',
                           fresh=['_elementtree'])
+cET_alias = import_fresh_module('xml.etree.cElementTree',
+                                fresh=['_elementtree', 'xml.etree'],
+                                deprecated=True)
 
 
 @unittest.skipUnless(cET, 'requires _elementtree')
@@ -168,6 +171,14 @@ class MiscTests(unittest.TestCase):
 
 
 @unittest.skipUnless(cET, 'requires _elementtree')
+class TestAliasWorking(unittest.TestCase):
+    # Test that the cET alias module is alive
+    def test_alias_working(self):
+        e = cET_alias.Element('foo')
+        self.assertEqual(e.tag, 'foo')
+
+
+@unittest.skipUnless(cET, 'requires _elementtree')
 @support.cpython_only
 class TestAcceleratorImported(unittest.TestCase):
     # Test that the C accelerator was imported, as expected
@@ -175,6 +186,9 @@ class TestAcceleratorImported(unittest.TestCase):
         # SubElement is a function so it retains _elementtree as its module.
         self.assertEqual(cET.SubElement.__module__, '_elementtree')
 
+    def test_correct_import_cET_alias(self):
+        self.assertEqual(cET_alias.SubElement.__module__, '_elementtree')
+
     def test_parser_comes_from_C(self):
         # The type of methods defined in Python code is types.FunctionType,
         # while the type of methods defined inside _elementtree is
@@ -214,6 +228,7 @@ def test_main():
     # Run the tests specific to the C implementation
     support.run_unittest(
         MiscTests,
+        TestAliasWorking,
         TestAcceleratorImported,
         SizeofTest,
         )
diff --git a/Lib/xml/etree/cElementTree.py b/Lib/xml/etree/cElementTree.py
new file mode 100644
index 0000000..368e679
--- /dev/null
+++ b/Lib/xml/etree/cElementTree.py
@@ -0,0 +1,3 @@
+# Deprecated alias for xml.etree.ElementTree
+
+from xml.etree.ElementTree import *