diff --git a/tests/test_extensions/test_ext_autosummary.py b/tests/test_extensions/test_ext_autosummary.py
index d1ea3d1ac..a6bf97a22 100644
--- a/tests/test_extensions/test_ext_autosummary.py
+++ b/tests/test_extensions/test_ext_autosummary.py
@@ -3,6 +3,7 @@
 import sys
 from io import StringIO
 from unittest.mock import Mock, patch
+from xml.etree.ElementTree import Element
 
 import pytest
 from docutils import nodes
@@ -45,7 +46,7 @@ def _unload_target_module():
 
 
 def test_mangle_signature():
-    TEST = """
+    TEST_SIGNATURE = """
     () :: ()
     (a, b, c, d, e) :: (a, b, c, d, e)
     (a, b, c=1, d=2, e=3) :: (a, b[, c, d, e])
@@ -66,7 +67,11 @@ def test_mangle_signature():
     (a: Tuple[int, str], b: int) -> str :: (a, b)
     """
 
-    TEST = [[y.strip() for y in x.split('::')] for x in TEST.split('\n') if '::' in x]
+    TEST = [
+        list(map(str.strip, x.split('::')))
+        for x in TEST_SIGNATURE.split('\n')
+        if '::' in x
+    ]
     for inp, outp in TEST:
         res = mangle_signature(inp).strip().replace('\u00a0', ' ')
         assert res == outp, f"'{inp}' -> '{res}' != '{outp}'"
@@ -206,7 +211,7 @@ def test_get_items_summary(make_app, app_params):
     assert autosummary_items['func'] == func_attrs
 
 
-def str_content(elem):
+def str_content(elem: Element) -> str:
     if elem.text is not None:
         return elem.text
     else:
diff --git a/tests/test_extensions/test_ext_napoleon.py b/tests/test_extensions/test_ext_napoleon.py
index 1175d6bec..9fd9c2d12 100644
--- a/tests/test_extensions/test_ext_napoleon.py
+++ b/tests/test_extensions/test_ext_napoleon.py
@@ -2,6 +2,7 @@
 
 import functools
 from collections import namedtuple
+from typing import Any
 from unittest import mock
 
 import pytest
@@ -141,7 +142,14 @@ class TestSetup:
 
 
 class TestSkipMember:
-    def assert_skip(self, what, member, obj, expect_default_skip, config_name):
+    def assert_skip(
+        self,
+        what: str,
+        member: str,
+        obj: Any,
+        expect_default_skip: bool,
+        config_name: str,
+    ) -> None:
         skip = True
         app = mock.Mock()
         app.config = Config()
diff --git a/tests/test_util/test_util_nodes.py b/tests/test_util/test_util_nodes.py
index 800dcc2b6..a330eff36 100644
--- a/tests/test_util/test_util_nodes.py
+++ b/tests/test_util/test_util_nodes.py
@@ -4,7 +4,7 @@ from __future__ import annotations
 
 import warnings
 from textwrap import dedent
-from typing import Any
+from typing import TYPE_CHECKING, Any
 
 import pytest
 from docutils import frontend, nodes
@@ -21,12 +21,15 @@ from sphinx.util.nodes import (
     split_explicit_title,
 )
 
+if TYPE_CHECKING:
+    from docutils.nodes import document
 
-def _transform(doctree):
+
+def _transform(doctree) -> None:
     ApplySourceWorkaround(doctree).apply()
 
 
-def create_new_document():
+def create_new_document() -> document:
     with warnings.catch_warnings():
         warnings.filterwarnings('ignore', category=DeprecationWarning)
         # DeprecationWarning: The frontend.OptionParser class will be replaced
@@ -44,7 +47,7 @@ def _get_doctree(text):
     return document
 
 
-def assert_node_count(messages, node_type, expect_count):
+def assert_node_count(messages, node_type, expect_count) -> None:
     count = 0
     node_list = [node for node, msg in messages]
     for node in node_list: