diff --git a/tests/conftest.py b/tests/conftest.py
index f0ca478ba1..b884f132f7 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -14,18 +14,14 @@ import sphinx
 import sphinx.locale
 from sphinx.testing.util import _clean_up_global_state
 
+from tests.utils import TEST_ROOTS_DIR
+
 if TYPE_CHECKING:
     from collections.abc import Callable, Iterator
     from typing import Any
 
     from sphinx.testing.util import SphinxTestApp
 
-_TESTS_ROOT = Path(__file__).resolve().parent
-if 'CI' in os.environ and (_TESTS_ROOT / 'roots-read-only').is_dir():
-    _ROOTS_DIR = _TESTS_ROOT / 'roots-read-only'
-else:
-    _ROOTS_DIR = _TESTS_ROOT / 'roots'
-
 
 def _init_console(
     locale_dir: str | os.PathLike[str] | None = sphinx.locale._LOCALE_DIR,
@@ -45,14 +41,14 @@ sphinx.locale.init_console = _init_console
 pytest_plugins = ['sphinx.testing.fixtures']
 
 # Exclude 'roots' dirs for pytest test collector
-collect_ignore = ['roots']
+collect_ignore = ['roots', 'roots-read-only']
 
 os.environ['SPHINX_AUTODOC_RELOAD_MODULES'] = '1'
 
 
 @pytest.fixture(scope='session')
 def rootdir() -> Path:
-    return _ROOTS_DIR
+    return TEST_ROOTS_DIR
 
 
 def pytest_report_header(config: pytest.Config) -> str:
@@ -61,7 +57,7 @@ def pytest_report_header(config: pytest.Config) -> str:
     ]
     if sys.version_info[:2] >= (3, 13):
         lines.append(f'GIL enabled?: {sys._is_gil_enabled()}')
-    lines.append(f'test roots directory: {_ROOTS_DIR}')
+    lines.append(f'test roots directory: {TEST_ROOTS_DIR}')
     if hasattr(config, '_tmp_path_factory'):
         lines.append(f'base tmp_path: {config._tmp_path_factory.getbasetemp()}')
     return '\n'.join(lines)
diff --git a/tests/test_util/test_util_logging.py b/tests/test_util/test_util_logging.py
index c21434a841..2eee35ce84 100644
--- a/tests/test_util/test_util_logging.py
+++ b/tests/test_util/test_util_logging.py
@@ -18,7 +18,7 @@ from sphinx.util.console import colorize
 from sphinx.util.logging import is_suppressed_warning, prefixed_warnings
 from sphinx.util.parallel import ParallelTasks
 
-from tests.utils import TESTS_ROOT
+from tests.utils import TEST_ROOTS_DIR
 
 if TYPE_CHECKING:
     from sphinx.testing.util import SphinxTestApp
@@ -297,7 +297,7 @@ def force_colors():
 def test_log_no_ansi_colors(tmp_path):
     with force_colors():
         wfile = tmp_path / 'warnings.txt'
-        srcdir = TESTS_ROOT / 'roots' / 'test-nitpicky-warnings'
+        srcdir = TEST_ROOTS_DIR / 'test-nitpicky-warnings'
         argv = list(map(str, ['-b', 'html', srcdir, tmp_path, '-n', '-w', wfile]))
         retcode = build_main(argv)
         assert retcode == 0
diff --git a/tests/utils.py b/tests/utils.py
index 59757edbd9..b75f9cc1c4 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -2,6 +2,7 @@ from __future__ import annotations
 
 __all__ = ('http_server',)
 
+import os
 import socket
 from contextlib import contextmanager
 from http.server import ThreadingHTTPServer
@@ -19,10 +20,16 @@ if TYPE_CHECKING:
 
     from sphinx.application import Sphinx
 
+TESTS_ROOT: Final[Path] = Path(__file__).resolve().parent
+TEST_ROOTS_DIR: Final[Path] = TESTS_ROOT / (
+    'roots-read-only'
+    if 'CI' in os.environ and (TESTS_ROOT / 'roots-read-only').is_dir()
+    else 'roots'
+)
+
 # Generated with:
 # $ openssl req -new -x509 -days 3650 -nodes -out cert.pem \
 #     -keyout cert.pem -addext "subjectAltName = DNS:localhost"
-TESTS_ROOT: Final[Path] = Path(__file__).resolve().parent
 CERT_FILE: Final[str] = str(TESTS_ROOT / 'certs' / 'cert.pem')