gh-128595: Add test class helper to force no terminal colour

Lib/test/support/__init__.py

@@ -17,6 +17,7 @@
 import types
 import unittest
 import warnings
+from collections.abc import Callable
 
 
 __all__ = [
@@ -60,6 +61,7 @@
     "skip_on_s390x",
     "without_optimizer",
     "force_not_colorized",
+    "force_not_colorized_test_class",
     "BrokenIter",
     "in_systemd_nspawn_sync_suppressed",
     "run_no_yield_async_fn", "run_yielding_async_fn", "async_yield",
@@ -2832,29 +2834,63 @@ def is_slot_wrapper(name, value):
             yield name, True
 
 
+def _disable_terminal_color():
+    import _colorize
+
+    original_fn = _colorize.can_colorize
+    variables = {
+        "PYTHON_COLORS": None,
+        "FORCE_COLOR": None,
+        "NO_COLOR": None,
+    }
+    for key in variables:
+        variables[key] = os.environ.pop(key, None)
+    os.environ["NO_COLOR"] = "1"
+    _colorize.can_colorize = lambda: False
+    return original_fn, variables
+
+
+def _re_enable_terminal_color(original_fn, variables):
+    import _colorize
+
+    _colorize.can_colorize = original_fn
+    del os.environ["NO_COLOR"]
+    for key, value in variables.items():
+        if value is not None:
+            os.environ[key] = value
+
+
 def force_not_colorized(func):
     """Force the terminal not to be colorized."""
     @functools.wraps(func)
     def wrapper(*args, **kwargs):
-        import _colorize
-        original_fn = _colorize.can_colorize
-        variables: dict[str, str | None] = {
-            "PYTHON_COLORS": None, "FORCE_COLOR": None, "NO_COLOR": None
-        }
         try:
-            for key in variables:
-                variables[key] = os.environ.pop(key, None)
-            os.environ["NO_COLOR"] = "1"
-            _colorize.can_colorize = lambda: False
+            original_fn, variables = _disable_terminal_color()
             return func(*args, **kwargs)
         finally:
-            _colorize.can_colorize = original_fn
-            del os.environ["NO_COLOR"]
-            for key, value in variables.items():
-                if value is not None:
-                    os.environ[key] = value
+            _re_enable_terminal_color(original_fn, variables)
     return wrapper
 
+def force_not_colorized_test_class(cls):
+    """Force the terminal not to be colorized."""
+    original_setup = cls.setUp
+    original_teardown = cls.tearDown
+
+    @functools.wraps(cls.setUp)
+    def setUp_wrapper(self, *args, **kwargs):
+        self._original_fn, self._variables = _disable_terminal_color()
+
+        return original_setup(self, *args, **kwargs)
+
+    @functools.wraps(cls.tearDown)
+    def tearDown_wrapper(self, *args, **kwargs):
+        _re_enable_terminal_color(self._original_fn, self._variables)
+        return original_teardown(self, *args, **kwargs)
+
+    cls.setUp = setUp_wrapper
+    cls.tearDown = tearDown_wrapper
+    return cls
+
 
 def initialized_with_pyrepl():
     """Detect whether PyREPL was used during Python initialization."""

Lib/test/test_code_module.py

@@ -5,9 +5,9 @@
 from textwrap import dedent
 from contextlib import ExitStack
 from unittest import mock
+from test.support import force_not_colorized_test_class
 from test.support import import_helper
 
-
 code = import_helper.import_module('code')
 
 
@@ -30,6 +30,7 @@ def mock_sys(self):
         del self.sysmod.ps2
 
 
+@force_not_colorized_test_class
 class TestInteractiveConsole(unittest.TestCase, MockSys):
     maxDiff = None
 

Lib/test/test_traceback.py

@@ -21,7 +21,7 @@
 from test.support.os_helper import TESTFN, unlink
 from test.support.script_helper import assert_python_ok, assert_python_failure
 from test.support.import_helper import forget
-from test.support import force_not_colorized
+from test.support import force_not_colorized, force_not_colorized_test_class
 
 import json
 import textwrap
@@ -1712,6 +1712,7 @@ def f():
 
 
 @requires_debug_ranges()
+@force_not_colorized_test_class
 class PurePythonTracebackErrorCaretTests(
     PurePythonExceptionFormattingMixin,
     TracebackErrorLocationCaretTestBase,
@@ -1725,6 +1726,7 @@ class PurePythonTracebackErrorCaretTests(
 
 @cpython_only
 @requires_debug_ranges()
+@force_not_colorized_test_class
 class CPythonTracebackErrorCaretTests(
     CAPIExceptionFormattingMixin,
     TracebackErrorLocationCaretTestBase,
@@ -1736,6 +1738,7 @@ class CPythonTracebackErrorCaretTests(
 
 @cpython_only
 @requires_debug_ranges()
+@force_not_colorized_test_class
 class CPythonTracebackLegacyErrorCaretTests(
     CAPIExceptionFormattingLegacyMixin,
     TracebackErrorLocationCaretTestBase,
@@ -2149,10 +2152,12 @@ def test_print_exception_bad_type_python(self):
 boundaries = re.compile(
     '(%s|%s)' % (re.escape(cause_message), re.escape(context_message)))
 
+@force_not_colorized_test_class
 class TestTracebackFormat(unittest.TestCase, TracebackFormatMixin):
     pass
 
 @cpython_only
+@force_not_colorized_test_class
 class TestFallbackTracebackFormat(unittest.TestCase, TracebackFormatMixin):
     DEBUG_RANGES = False
     def setUp(self) -> None:
@@ -2940,6 +2945,7 @@ def f():
         self.assertEqual(report, expected)
 
 
+@force_not_colorized_test_class
 class PyExcReportingTests(BaseExceptionReportingTests, unittest.TestCase):
     #
     # This checks reporting through the 'traceback' module, with both
@@ -2956,6 +2962,7 @@ def get_report(self, e):
         return s
 
 
+@force_not_colorized_test_class
 class CExcReportingTests(BaseExceptionReportingTests, unittest.TestCase):
     #
     # This checks built-in reporting by the interpreter.