From fbf0843e39e01ec8a8295f6475065b08053f13dd Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Fri, 17 Oct 2025 14:21:39 +0300
Subject: [PATCH] gh-135801: Add tests for filtering warnings by module
 (GH-140240)

---
 Lib/test/test_warnings/__init__.py | 79 ++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)

diff --git a/Lib/test/test_warnings/__init__.py b/Lib/test/test_warnings/__init__.py
index 260fae8fe24..157852cfa91 100644
--- a/Lib/test/test_warnings/__init__.py
+++ b/Lib/test/test_warnings/__init__.py
@@ -241,6 +241,85 @@ def test_once(self):
                                     42)
             self.assertEqual(len(w), 0)
 
+    def test_filter_module(self):
+        MS_WINDOWS = (sys.platform == 'win32')
+        with self.module.catch_warnings(record=True) as w:
+            self.module.simplefilter('error')
+            self.module.filterwarnings('always', module=r'package\.module\z')
+            self.module.warn_explicit('msg', UserWarning, 'filename', 42,
+                                      module='package.module')
+            self.assertEqual(len(w), 1)
+            with self.assertRaises(UserWarning):
+                self.module.warn_explicit('msg', UserWarning, '/path/to/package/module', 42)
+            with self.assertRaises(UserWarning):
+                self.module.warn_explicit('msg', UserWarning, '/path/to/package/module.py', 42)
+
+        with self.module.catch_warnings(record=True) as w:
+            self.module.simplefilter('error')
+            self.module.filterwarnings('always', module='package')
+            self.module.warn_explicit('msg', UserWarning, 'filename', 42,
+                                      module='package.module')
+            self.assertEqual(len(w), 1)
+            with self.assertRaises(UserWarning):
+                self.module.warn_explicit('msg', UserWarning, 'filename', 42,
+                                          module='other.package.module')
+            with self.assertRaises(UserWarning):
+                self.module.warn_explicit('msg', UserWarning, '/path/to/otherpackage/module.py', 42)
+
+        with self.module.catch_warnings(record=True) as w:
+            self.module.simplefilter('error')
+            self.module.filterwarnings('always', module=r'/path/to/package/module\z')
+            self.module.warn_explicit('msg', UserWarning, '/path/to/package/module', 42)
+            self.assertEqual(len(w), 1)
+            self.module.warn_explicit('msg', UserWarning, '/path/to/package/module.py', 42)
+            self.assertEqual(len(w), 2)
+            with self.assertRaises(UserWarning):
+                self.module.warn_explicit('msg', UserWarning, '/PATH/TO/PACKAGE/MODULE', 42)
+            if MS_WINDOWS:
+                if self.module is py_warnings:
+                    self.module.warn_explicit('msg', UserWarning, r'/path/to/package/module.PY', 42)
+                    self.assertEqual(len(w), 3)
+                with self.assertRaises(UserWarning):
+                    self.module.warn_explicit('msg', UserWarning, r'/path/to/package/module/__init__.py', 42)
+                with self.assertRaises(UserWarning):
+                    self.module.warn_explicit('msg', UserWarning, r'/path/to/package/module.pyw', 42)
+                with self.assertRaises(UserWarning):
+                    self.module.warn_explicit('msg', UserWarning, r'\path\to\package\module', 42)
+
+        with self.module.catch_warnings(record=True) as w:
+            self.module.simplefilter('error')
+            self.module.filterwarnings('always', module=r'/path/to/package/__init__\z')
+            self.module.warn_explicit('msg', UserWarning, '/path/to/package/__init__.py', 42)
+            self.assertEqual(len(w), 1)
+            self.module.warn_explicit('msg', UserWarning, '/path/to/package/__init__', 42)
+            self.assertEqual(len(w), 2)
+
+        if MS_WINDOWS:
+            with self.module.catch_warnings(record=True) as w:
+                self.module.simplefilter('error')
+                self.module.filterwarnings('always', module=r'C:\\path\\to\\package\\module\z')
+                self.module.warn_explicit('msg', UserWarning, r'C:\path\to\package\module', 42)
+                self.assertEqual(len(w), 1)
+                self.module.warn_explicit('msg', UserWarning, r'C:\path\to\package\module.py', 42)
+                self.assertEqual(len(w), 2)
+                if self.module is py_warnings:
+                    self.module.warn_explicit('msg', UserWarning, r'C:\path\to\package\module.PY', 42)
+                    self.assertEqual(len(w), 3)
+                with self.assertRaises(UserWarning):
+                    self.module.warn_explicit('msg', UserWarning, r'C:\path\to\package\module.pyw', 42)
+                with self.assertRaises(UserWarning):
+                    self.module.warn_explicit('msg', UserWarning, r'C:\PATH\TO\PACKAGE\MODULE', 42)
+                with self.assertRaises(UserWarning):
+                    self.module.warn_explicit('msg', UserWarning, r'C:/path/to/package/module', 42)
+                with self.assertRaises(UserWarning):
+                    self.module.warn_explicit('msg', UserWarning, r'C:\path\to\package\module\__init__.py', 42)
+
+        with self.module.catch_warnings(record=True) as w:
+            self.module.simplefilter('error')
+            self.module.filterwarnings('always', module=r'<unknown>\z')
+            self.module.warn_explicit('msg', UserWarning, '', 42)
+            self.assertEqual(len(w), 1)
+
     def test_module_globals(self):
         with self.module.catch_warnings(record=True) as w:
             self.module.simplefilter("always", UserWarning)