gh-152548: Move per-test imports into the test methods in test_audit

Keep at module level only what the old audit-tests.py had there (os, sys,
unittest.mock) plus the test framework (unittest, support); import the
modules under test and the helpers (import_helper, os_helper,
script_helper, textwrap) inside the methods that use them.

For the optional modules a requires_module() decorator runs the
import_helper check in the parent process, so a missing module skips the
test without first spawning an @isolated() subprocess.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: serhiy-storchaka

Lib/test/test_audit.py

@@ -9,12 +9,8 @@
 
 import os
 import sys
-import textwrap
 import unittest
 from test import support
-from test.support import import_helper
-from test.support import os_helper
-from test.support import script_helper
 from unittest.mock import ANY
 
 
@@ -55,6 +51,24 @@ def __call__(self, event, args):
             raise self.exc_type("saw event " + event)
 
 
+def requires_module(name):
+    """Skip the test, in the parent process, if module *name* is unavailable.
+
+    Checking here means a missing module skips the test without first spawning
+    the @isolated() subprocess.
+    """
+    import functools
+
+    def decorator(func):
+        @functools.wraps(func)
+        def wrapper(self):
+            from test.support import import_helper
+            import_helper.import_module(name)
+            return func(self)
+        return wrapper
+    return decorator
+
+
 class AuditTest(unittest.TestCase):
     maxDiff = None
 
@@ -87,6 +101,7 @@ def test_block_add_hook_baseexception(self):
     @support.isolated()
     def test_marshal(self):
         import marshal
+        from test.support import os_helper
 
         o = ("a", "b", "c", 1, 2, 3)
         payload = marshal.dumps(o)
@@ -169,6 +184,8 @@ class C(A):
 
     @support.isolated()
     def test_open(self):
+        from test.support import os_helper
+
         testfn = os_helper.TESTFN
 
         # SSLContext.load_dh_params uses Py_fopen() rather than normal open()
@@ -304,9 +321,9 @@ def test_mmap(self):
             mmap.mmap(-1, 8)
         self.assertEqual(hook.seen[0][1][:2], (-1, 8))
 
+    @requires_module("ctypes")
     @support.isolated()
     def test_ctypes_call_function(self):
-        import_helper.import_module("ctypes")
         import ctypes
         import _ctypes
 
@@ -330,9 +347,9 @@ def test_ctypes_call_function(self):
             self.assertIn("ctypes.call_function", hook.seen_events)
             self.assertIn("ctypes.string_at", hook.seen_events)
 
+    @requires_module("_posixsubprocess")
     @support.isolated()
     def test_posixsubprocess(self):
-        import_helper.import_module("_posixsubprocess")
         import multiprocessing.util
 
         exe = b"xxx"
@@ -344,6 +361,9 @@ def test_posixsubprocess(self):
 
     @support.requires_subprocess()
     def test_excepthook(self):
+        import textwrap
+        from test.support import script_helper
+
         # The "sys.excepthook" audit event fires only for an exception that goes
         # uncaught to the top level of the interpreter, so this case cannot use
         # @isolated() (whose test body runs under unittest, which catches the
@@ -375,9 +395,10 @@ def hook(event, args):
             stderr.decode(),
         )
 
+    @requires_module("_testcapi")
     @support.isolated()
     def test_unraisablehook(self):
-        _testcapi = import_helper.import_module("_testcapi")
+        import _testcapi
 
         def unraisablehook(hookargs):
             pass
@@ -401,9 +422,10 @@ def hook(event, args):
         self.assertEqual(args[1].err_msg,
                          "Exception ignored for audit hook test")
 
+    @requires_module("winreg")
     @support.isolated()
     def test_winreg(self):
-        winreg = import_helper.import_module("winreg")
+        import winreg
 
         events = []
 
@@ -428,6 +450,7 @@ def hook(event, args):
         self.assertEqual(events[3], ("winreg.EnumKey", (hkey, 10000)))
         self.assertEqual(events[4], ("winreg.PyHKEY.Detach", (hkey,)))
 
+    @requires_module("socket")
     @support.isolated()
     def test_socket(self):
         import socket
@@ -482,9 +505,10 @@ def hook(event, args):
             ["gc.get_objects", "gc.get_referrers", "gc.get_referents"])
 
     @support.requires_resource('network')
+    @requires_module("http.client")
     @support.isolated()
     def test_http(self):
-        http_client = import_helper.import_module("http.client")
+        import http.client
 
         events = []
 
@@ -494,7 +518,7 @@ def hook(event, args):
 
         sys.addaudithook(hook)
 
-        conn = http_client.HTTPConnection('www.python.org')
+        conn = http.client.HTTPConnection('www.python.org')
         sent = True
         try:
             conn.request('GET', '/')
@@ -509,9 +533,10 @@ def hook(event, args):
             self.assertEqual(events[1][0], "http.client.send")
             self.assertIn(b'HTTP', events[1][1][0])
 
+    @requires_module("sqlite3")
     @support.isolated()
     def test_sqlite3(self):
-        sqlite3 = import_helper.import_module("sqlite3")
+        import sqlite3
 
         events = []
 
@@ -608,9 +633,10 @@ def __call__(self):
             ],
         )
 
+    @requires_module("_wmi")
     @support.isolated()
     def test_wmi_exec_query(self):
-        _wmi = import_helper.import_module("_wmi")
+        import _wmi
 
         events = []
 
@@ -632,9 +658,10 @@ def hook(event, args):
         self.assertEqual(events[0][1][0],
                          "SELECT * FROM Win32_OperatingSystem")
 
+    @requires_module("syslog")
     @support.isolated()
     def test_syslog(self):
-        syslog = import_helper.import_module("syslog")
+        import syslog
 
         events = []
 
@@ -729,9 +756,10 @@ def hook(event, args):
         self.assertEqual(
             events, [("sys.monitoring.register_callback", (None,))])
 
+    @requires_module("_winapi")
     @support.isolated()
     def test_winapi_createnamedpipe(self):
-        _winapi = import_helper.import_module("_winapi")
+        import _winapi
 
         pipe_name = r"\\.\pipe\LOCAL\test_winapi_createnamed_pipe"