fix color handling in test runner

CHANGES.rst

@@ -10,6 +10,8 @@ Unreleased
     multiple lines. :issue:`2697`
 -   Fixed issue that prevented a default value of ``""`` from being displayed in
     the help for an option. :issue:`2500`
+-   The test runner handles stripping color consistently on Windows.
+    :issue:`2705`
 
 
 Version 8.1.7

src/click/testing.py

@@ -8,6 +8,7 @@
 import typing as t
 from types import TracebackType
 
+from . import _compat
 from . import formatting
 from . import termui
 from . import utils
@@ -315,6 +316,7 @@ def should_strip_ansi(
         termui.hidden_prompt_func = hidden_input
         termui._getchar = _getchar
         utils.should_strip_ansi = should_strip_ansi  # type: ignore
+        _compat.should_strip_ansi = should_strip_ansi
 
         old_env = {}
         try:

tests/test_testing.py

@@ -5,7 +5,6 @@
 import pytest
 
 import click
-from click._compat import WIN
 from click.testing import CliRunner
 
 
@@ -184,7 +183,6 @@ def cli():
     assert result.exit_code == 1
 
 
-@pytest.mark.skipif(WIN, reason="Test does not make sense on Windows.")
 def test_with_color():
     @click.command()
     def cli():