diff --git a/src/_pytest/pytester.py b/src/_pytest/pytester.py
index 99d33954d..f93e9c94a 100644
--- a/src/_pytest/pytester.py
+++ b/src/_pytest/pytester.py
@@ -121,13 +121,18 @@ def pytest_configure(config: Config) -> None:
 
 class LsofFdLeakChecker:
     def get_open_files(self) -> List[Tuple[str, str]]:
+        if sys.version_info >= (3, 11):
+            # New in Python 3.11, ignores utf-8 mode
+            encoding = locale.getencoding()
+        else:
+            encoding = locale.getpreferredencoding(False)
         out = subprocess.run(
             ("lsof", "-Ffn0", "-p", str(os.getpid())),
             stdout=subprocess.PIPE,
             stderr=subprocess.DEVNULL,
             check=True,
             text=True,
-            encoding=locale.getpreferredencoding(False),
+            encoding=encoding,
         ).stdout
 
         def isopen(line: str) -> bool:
diff --git a/testing/test_parseopt.py b/testing/test_parseopt.py
index b6df035aa..1b80883ee 100644
--- a/testing/test_parseopt.py
+++ b/testing/test_parseopt.py
@@ -290,10 +290,10 @@ class TestParser:
 
 
 def test_argcomplete(pytester: Pytester, monkeypatch: MonkeyPatch) -> None:
-    try:
+    if sys.version_info >= (3, 11):
         # New in Python 3.11, ignores utf-8 mode
-        encoding = locale.getencoding()  # type: ignore[attr-defined]
-    except AttributeError:
+        encoding = locale.getencoding()
+    else:
         encoding = locale.getpreferredencoding(False)
     try:
         bash_version = subprocess.run(