diff --git a/pyproject.toml b/pyproject.toml
index 88303fa..f5b33b4 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -176,6 +176,7 @@ max-complexity = 15
   "D103", # Missing docstring in public function
   "D104", # Missing docstring in public package
   "S101", # Use of assert detected
+  "S603", # `subprocess` call: check for execution of untrusted input
   "PT011", # {exc} is too broad, set the `match` parameter or use a more specific exception.
   "PLR2004", # Magic value used in comparison, consider replacing {value} with a constant variable
   "S311", # Standard pseudo-random generators are not suitable for cryptographic purposes
diff --git a/tests/test_async_client.py b/tests/test_async_client.py
index 98b237c..9c0ce4f 100644
--- a/tests/test_async_client.py
+++ b/tests/test_async_client.py
@@ -553,7 +553,7 @@ def test_invalid_proxy(proxy: Any) -> None:
 
 
 def test_proxy_connect_timeout() -> None:
-    async def inner():
+    async def inner() -> None:
         async with HttpClient(
             connect_timeout=1.0, proxy=[Proxy(UNROUTABLE_PROXY)]
         ) as client:
@@ -564,7 +564,7 @@ async def inner():
 
 
 def test_proxy_request_timeout(httpd_blackhole: BlackholeHttpd) -> None:
-    async def inner():
+    async def inner() -> None:
         async with HttpClient(
             timeout=1.0, proxy=[Proxy(httpd_blackhole.prefix)]
         ) as client:
@@ -575,7 +575,7 @@ async def inner():
 
 
 def test_proxy_get(httpd: Httpd, proxy: Proxy) -> None:
-    async def inner():
+    async def inner() -> None:
         async with HttpClient(
             connect_timeout=1.0, timeout=3.0, proxy=[Proxy(proxy.url)]
         ) as client:
diff --git a/tests/tinyproxy.py b/tests/tinyproxy.py
index bacfd19..af50f8c 100644
--- a/tests/tinyproxy.py
+++ b/tests/tinyproxy.py
@@ -11,7 +11,6 @@
 import queue
 import subprocess
 import threading
-import time
 from pathlib import Path
 from tempfile import TemporaryDirectory
 from types import TracebackType