From 16910fc26413913bdbc7cd2b81813f1649a3a0c7 Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Mon, 19 Jan 2026 15:32:40 +0000
Subject: [PATCH] Improve test coverage for _markupbase, _aix_support,
 _ios_support and enhance README.rst

- Added Lib/test/test_markupbase.py with comprehensive tests for ParserBase.
- Added Lib/test/test_aix_support.py using mocks to test AIX platform logic.
- Added Lib/test/test_ios_support.py using mocks to test iOS platform logic.
- Updated README.rst with a "Quick Start for Contributors" section including build, test, and dev environment setup instructions.
- Removed temporary analysis files.
---
 Lib/test/test_aix_support.py |  62 ++++++++++
 Lib/test/test_ios_support.py |  62 ++++++++++
 Lib/test/test_markupbase.py  | 218 +++++++++++++++++++++++++++++++++++
 README.rst                   |  17 +++
 4 files changed, 359 insertions(+)
 create mode 100644 Lib/test/test_aix_support.py
 create mode 100644 Lib/test/test_ios_support.py
 create mode 100644 Lib/test/test_markupbase.py

diff --git a/Lib/test/test_aix_support.py b/Lib/test/test_aix_support.py
new file mode 100644
index 000000000000000..dcb54c004565275
--- /dev/null
+++ b/Lib/test/test_aix_support.py
@@ -0,0 +1,62 @@
+import unittest
+from unittest import mock
+from test import support
+import _aix_support
+
+class TestAIXSupport(unittest.TestCase):
+    def test_aix_vrtl(self):
+        # _aix_vrtl takes the last character of the version string as the first element of the list
+        self.assertEqual(_aix_support._aix_vrtl("7.1.4.34"), [7, 1, 4])
+        self.assertEqual(_aix_support._aix_vrtl("6.1.0.0"), [6, 1, 0])
+        self.assertEqual(_aix_support._aix_vrtl("1.2.3.4"), [1, 2, 3])
+
+    def test_aix_tag(self):
+        with mock.patch("sys.maxsize", 2**31 - 1):
+            self.assertEqual(_aix_support._aix_tag([6, 1, 7], 1415), "aix-6107-1415-32")
+        with mock.patch("sys.maxsize", 2**63 - 1):
+            self.assertEqual(_aix_support._aix_tag([6, 1, 7], 1415), "aix-6107-1415-64")
+        # Default build date
+        with mock.patch("sys.maxsize", 2**63 - 1):
+            self.assertEqual(_aix_support._aix_tag([7, 1, 0], 0), "aix-7100-9988-64")
+
+    @mock.patch("subprocess.check_output")
+    def test_aix_bos_rte(self, mock_check_output):
+        mock_check_output.return_value = b"something:something:7.1.4.34:something:something:something:1806"
+        vrmf, bd = _aix_support._aix_bos_rte()
+        self.assertEqual(vrmf, "7.1.4.34")
+        self.assertEqual(bd, 1806)
+
+        # No build date
+        mock_check_output.return_value = b"something:something:7.1.4.34:something:something:something:"
+        vrmf, bd = _aix_support._aix_bos_rte()
+        self.assertEqual(bd, 9988)
+
+    @mock.patch("_aix_support._aix_bos_rte")
+    @mock.patch("sys.maxsize", 2**63 - 1)
+    def test_aix_platform(self, mock_bos_rte):
+        mock_bos_rte.return_value = ("7.1.4.34", 1806)
+        self.assertEqual(_aix_support.aix_platform(), "aix-7104-1806-64")
+
+    @mock.patch("sysconfig.get_config_var")
+    def test_aix_bgt(self, mock_get_config_var):
+        mock_get_config_var.return_value = "powerpc-ibm-aix7.1.4.0"
+        self.assertEqual(_aix_support._aix_bgt(), [7, 1, 4])
+
+        mock_get_config_var.return_value = None
+        with self.assertRaises(ValueError):
+            _aix_support._aix_bgt()
+
+    @mock.patch("sysconfig.get_config_var")
+    @mock.patch("_aix_support._aix_bgt")
+    @mock.patch("sys.maxsize", 2**63 - 1)
+    def test_aix_buildtag(self, mock_aix_bgt, mock_get_config_var):
+        mock_aix_bgt.return_value = [7, 1, 4]
+        mock_get_config_var.return_value = "1806"
+        self.assertEqual(_aix_support.aix_buildtag(), "aix-7104-1806-64")
+
+        mock_get_config_var.return_value = "invalid"
+        with self.assertRaises(ValueError):
+            _aix_support.aix_buildtag()
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/Lib/test/test_ios_support.py b/Lib/test/test_ios_support.py
new file mode 100644
index 000000000000000..a78b93ca7ffd375
--- /dev/null
+++ b/Lib/test/test_ios_support.py
@@ -0,0 +1,62 @@
+import unittest
+from unittest import mock
+from test import support
+
+# Import the module under test. It's already in the path when running via regrtest.
+import _ios_support
+
+class TestIOSSupport(unittest.TestCase):
+    def test_get_platform_ios_no_objc(self):
+        with mock.patch("_ios_support.objc", None):
+            with mock.patch("sys.implementation._multiarch", "arm64-ios"):
+                self.assertIsNone(_ios_support.get_platform_ios())
+
+    def test_get_platform_ios_simulator(self):
+        # We need to mock objc and its methods
+        mock_objc = mock.Mock()
+        mock_objc.objc_getClass.return_value = 1
+        mock_objc.sel_registerName.return_value = 2
+
+        # mock_objc.objc_msgSend.side_effect is used multiple times
+        mock_objc.objc_msgSend.side_effect = [
+            10, # device
+            20, # systemVersion
+            30, # systemName
+            40, # model
+            b"iOS", # system
+            b"15.0", # release
+            b"iPhone" # model
+        ]
+
+        # We also need to mock c_void_p and c_char_p if they are missing in the environment
+        # as the module uses them from its own namespace.
+        with mock.patch("_ios_support.objc", mock_objc):
+            with mock.patch("_ios_support.c_void_p", "c_void_p", create=True):
+                with mock.patch("_ios_support.c_char_p", "c_char_p", create=True):
+                    with mock.patch("sys.implementation._multiarch", "x86_64-ios-simulator"):
+                        result = _ios_support.get_platform_ios()
+                        self.assertEqual(result, ("iOS", "15.0", "iPhone", True))
+
+    def test_get_platform_ios_device(self):
+        mock_objc = mock.Mock()
+        mock_objc.objc_getClass.return_value = 1
+        mock_objc.sel_registerName.return_value = 2
+        mock_objc.objc_msgSend.side_effect = [
+            10, # device
+            20, # systemVersion
+            30, # systemName
+            40, # model
+            b"iOS", # system
+            b"15.0", # release
+            b"iPhone" # model
+        ]
+
+        with mock.patch("_ios_support.objc", mock_objc):
+            with mock.patch("_ios_support.c_void_p", "c_void_p", create=True):
+                with mock.patch("_ios_support.c_char_p", "c_char_p", create=True):
+                    with mock.patch("sys.implementation._multiarch", "arm64-ios"):
+                        result = _ios_support.get_platform_ios()
+                        self.assertEqual(result, ("iOS", "15.0", "iPhone", False))
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/Lib/test/test_markupbase.py b/Lib/test/test_markupbase.py
new file mode 100644
index 000000000000000..235f99d33be1f3e
--- /dev/null
+++ b/Lib/test/test_markupbase.py
@@ -0,0 +1,218 @@
+import unittest
+from _markupbase import ParserBase
+
+class MockParser(ParserBase):
+    def __init__(self):
+        super().__init__()
+        self.rawdata = ""
+        self.reset()
+        self.decls = []
+        self.comments = []
+
+    def handle_decl(self, decl):
+        self.decls.append(decl)
+
+    def unknown_decl(self, data):
+        self.decls.append(data)
+
+    def handle_comment(self, data):
+        self.comments.append(data)
+
+class TestMarkupBase(unittest.TestCase):
+    def test_init_fail(self):
+        with self.assertRaisesRegex(RuntimeError, "_markupbase.ParserBase must be subclassed"):
+            ParserBase()
+
+    def test_updatepos(self):
+        parser = MockParser()
+        parser.rawdata = "abc\ndef\nghi"
+        parser.updatepos(0, 4)
+        self.assertEqual(parser.getpos(), (2, 0))
+        parser.updatepos(4, 6)
+        self.assertEqual(parser.getpos(), (2, 2))
+        parser.updatepos(6, 8)
+        self.assertEqual(parser.getpos(), (3, 0))
+
+        # No-op if i >= j
+        pos = parser.getpos()
+        parser.updatepos(8, 8)
+        self.assertEqual(parser.getpos(), pos)
+        parser.updatepos(9, 8)
+        self.assertEqual(parser.getpos(), pos)
+
+    def test_parse_comment(self):
+        parser = MockParser()
+        parser.rawdata = "<!--comment-->"
+        n = parser.parse_comment(0)
+        self.assertEqual(n, len(parser.rawdata))
+        self.assertEqual(parser.comments, ["comment"])
+
+        # No report
+        parser = MockParser()
+        parser.rawdata = "<!--comment-->"
+        n = parser.parse_comment(0, report=0)
+        self.assertEqual(n, len(parser.rawdata))
+        self.assertEqual(parser.comments, [])
+
+        # Incomplete
+        parser = MockParser()
+        parser.rawdata = "<!--comment"
+        n = parser.parse_comment(0)
+        self.assertEqual(n, -1)
+
+        # Unexpected call
+        parser = MockParser()
+        parser.rawdata = "NOT A COMMENT"
+        with self.assertRaises(AssertionError):
+            parser.parse_comment(0)
+
+    def test_parse_declaration(self):
+        parser = MockParser()
+        parser.rawdata = "<!DOCTYPE html>"
+        n = parser.parse_declaration(0)
+        self.assertEqual(n, len(parser.rawdata))
+        self.assertEqual(parser.decls, ["DOCTYPE html"])
+
+        # Empty comment <!>
+        parser = MockParser()
+        parser.rawdata = "<!>"
+        n = parser.parse_declaration(0)
+        self.assertEqual(n, 3)
+
+        # Incomplete
+        parser = MockParser()
+        parser.rawdata = "<!-"
+        n = parser.parse_declaration(0)
+        self.assertEqual(n, -1)
+
+        parser = MockParser()
+        parser.rawdata = "<!"
+        n = parser.parse_declaration(0)
+        self.assertEqual(n, -1)
+
+        # Unexpected call
+        parser = MockParser()
+        parser.rawdata = "NOT A DECL"
+        with self.assertRaises(AssertionError):
+            parser.parse_declaration(0)
+
+    def test_parse_marked_section(self):
+        parser = MockParser()
+        parser.rawdata = "<![CDATA[content]]>"
+        n = parser.parse_marked_section(0)
+        self.assertEqual(n, len(parser.rawdata))
+        self.assertEqual(parser.decls, ["CDATA[content"])
+
+        # MS Office extension
+        parser = MockParser()
+        parser.rawdata = "<![if word]>content<![endif]>"
+        n = parser.parse_marked_section(0)
+        self.assertEqual(n, len("<![if word]>"))
+        self.assertEqual(parser.decls, ["if word"])
+
+        # Incomplete
+        parser = MockParser()
+        parser.rawdata = "<![CDATA[content"
+        n = parser.parse_marked_section(0)
+        self.assertEqual(n, -1)
+
+        # Unexpected call
+        parser = MockParser()
+        parser.rawdata = "<!NOT MARKED"
+        with self.assertRaises(AssertionError):
+            parser.parse_marked_section(0)
+
+        # Unknown keyword
+        parser = MockParser()
+        parser.rawdata = "<![UNKNOWN keyword]]>"
+        with self.assertRaises(AssertionError):
+            parser.parse_marked_section(0)
+
+    def test_doctype_subset(self):
+        parser = MockParser()
+        parser.rawdata = "<!DOCTYPE html [ <!ELEMENT foo ANY> ]>"
+        n = parser.parse_declaration(0)
+        self.assertEqual(n, len(parser.rawdata))
+        self.assertEqual(parser.decls, ["DOCTYPE html [ <!ELEMENT foo ANY> ]"])
+
+        # Complex subset
+        parser = MockParser()
+        parser.rawdata = "<!DOCTYPE doc [ <!ENTITY e 'v'> <!ATTLIST a attr CDATA #REQUIRED> ]>"
+        n = parser.parse_declaration(0)
+        self.assertEqual(n, len(parser.rawdata))
+
+        # Subset with comments
+        parser = MockParser()
+        parser.rawdata = "<!DOCTYPE doc [ <!-- comment --> ]>"
+        n = parser.parse_declaration(0)
+        self.assertEqual(n, len(parser.rawdata))
+
+        # Subset with percentage (parameter entity)
+        parser = MockParser()
+        parser.rawdata = "<!DOCTYPE doc [ %name; ]>"
+        n = parser.parse_declaration(0)
+        self.assertEqual(n, len(parser.rawdata))
+
+    def test_scan_name_errors(self):
+        parser = MockParser()
+        parser.rawdata = "<!DOCTYPE " # incomplete name
+        n = parser.parse_declaration(0)
+        self.assertEqual(n, -1)
+
+        parser.rawdata = "<! " # not a name
+        with self.assertRaises(AssertionError):
+            parser.parse_declaration(0)
+
+    def test_parse_doctype_element(self):
+        parser = MockParser()
+        parser.rawdata = "<!ELEMENT name ANY>"
+        n = parser.parse_declaration(0)
+        self.assertEqual(parser.decls, ["ELEMENT name ANY"])
+
+    def test_parse_doctype_attlist(self):
+        parser = MockParser()
+        # Simplified attlist: name type [value] [#constraint]
+        parser.rawdata = "<!DOCTYPE doc [ <!ATTLIST el attr CDATA #IMPLIED> ]>"
+        n = parser.parse_declaration(0)
+        self.assertEqual(n, len(parser.rawdata))
+
+        # Enumerated type
+        parser.rawdata = "<!DOCTYPE doc [ <!ATTLIST el attr (a|b) 'a'> ]>"
+        n = parser.parse_declaration(0)
+        self.assertEqual(n, len(parser.rawdata))
+
+    def test_parse_doctype_notation(self):
+        parser = MockParser()
+        parser.rawdata = "<!DOCTYPE doc [ <!NOTATION n SYSTEM 's'> ]>"
+        n = parser.parse_declaration(0)
+        self.assertEqual(n, len(parser.rawdata))
+
+    def test_parse_doctype_entity(self):
+        parser = MockParser()
+        parser.rawdata = "<!DOCTYPE doc [ <!ENTITY % name 'v'> ]>"
+        n = parser.parse_declaration(0)
+        self.assertEqual(n, len(parser.rawdata))
+
+        parser.rawdata = "<!DOCTYPE doc [ <!ENTITY name 'v'> ]>"
+        n = parser.parse_declaration(0)
+        self.assertEqual(n, len(parser.rawdata))
+
+    def test_errors_in_subset(self):
+        parser = MockParser()
+        # Unexpected char in subset
+        parser.rawdata = "<!DOCTYPE doc [ ? ]>"
+        with self.assertRaises(AssertionError):
+            parser.parse_declaration(0)
+
+        # Unknown declaration in subset
+        parser.rawdata = "<!DOCTYPE doc [ <!UNKNOWN> ]>"
+        with self.assertRaises(AssertionError):
+            parser.parse_declaration(0)
+
+        # Unexpected char after subset
+        parser.rawdata = "<!DOCTYPE doc [ ] ? >"
+        with self.assertRaises(AssertionError):
+            parser.parse_declaration(0)
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/README.rst b/README.rst
index c507bf3b16ea4af..966e62527f68ed2 100644
--- a/README.rst
+++ b/README.rst
@@ -57,6 +57,23 @@ On Unix, Linux, BSD, macOS, and Cygwin::
 
 This will install Python as ``python3``.
 
+Quick Start for Contributors
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+1. **Clone the repository:**
+   ``git clone https://github.com/python/cpython.git``
+2. **Build Python:**
+   ``./configure --with-pydebug && make -j``
+3. **Run tests:**
+   - To run all tests: ``./python -m test``
+   - To run a specific test: ``./python -m test test_os``
+4. **Create a virtual environment for development:**
+   ``./python -m venv venv && source venv/bin/activate``
+5. **Install development tools:**
+   ``python -m pip install pre-commit ruff``
+6. **Install pre-commit hooks:**
+   ``pre-commit install``
+
 You can pass many options to the configure script; run ``./configure --help``
 to find out more.  On macOS case-insensitive file systems and on Cygwin,
 the executable is called ``python.exe``; elsewhere it's just ``python``.