[3.13] gh-128911: Add tests on the PyImport C API (#128915)

[vstinner]

• Add Modules/_testlimitedcapi/import.c
• Add Lib/test/test_capi/test_import.py
• Remove _testcapi.check_pyimport_addmodule(): tests already covered by newly added tests.

Co-authored-by: Serhiy Storchaka [email protected]
(cherry picked from commit d95ba9f)

• Issue: [C API] Add PyImport_ImportModuleAttr(mod_name, attr_name) helper function #128911

[vstinner]

@serhiy-storchaka: In Python 3.13, non-string names lead to crashes. I had to remove these tests:

diff --git a/Lib/test/test_capi/test_import.py b/Lib/test/test_capi/test_import.py
index 94f96728d91..3abd1cd7470 100644
--- a/Lib/test/test_capi/test_import.py
+++ b/Lib/test/test_capi/test_import.py
@@ -70,8 +70,6 @@ def check_addmodule(self, add_module, accept_nonstr=False):
         names = ['nonexistent']
         if accept_nonstr:
             names.append(b'\xff')  # non-UTF-8
-            # PyImport_AddModuleObject() accepts non-string names
-            names.append(tuple(['hashable non-string']))
         for name in names:
             with self.subTest(name=name):
                 self.assertNotIn(name, sys.modules)
@@ -311,9 +309,6 @@ def test_executecodemoduleobject(self):
 
         code = compile('attr = 1', '<test>', 'exec')
         self.assertRaises(TypeError, execute_code_func, [], code, NULL, NULL)
-        nonstring = tuple(['hashable non-string'])
-        self.assertRaises(AttributeError, execute_code_func, nonstring, code, NULL, NULL)
-        sys.modules.pop(nonstring, None)
         # CRASHES execute_code_func(NULL, code, NULL, NULL)
         # CRASHES execute_code_func(name, NULL, NULL, NULL)
 

[miss-islington-app]

Thanks @vstinner for the PR 🌮🎉.. I'm working now to backport this PR to: 3.12.
🐍🍒⛏🤖

[miss-islington-app]

Sorry, @vstinner, I could not cleanly backport this to 3.12 due to a conflict.
Please backport using cherry_picker on command line.

cherry_picker 34ded1a1a10204635cad27830fcbee2f8547e8ed 3.12

[vstinner]

The change cannot be backported to 3.12: Modules/_testlimitedcapi.c doesn't exist in the 3.12 branch.

[bedevere-app]

GH-128989 is a backport of this pull request to the 3.12 branch.