diff --git a/pyproject.toml b/pyproject.toml
index 95a6e100..b80ad3ae 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -53,7 +53,11 @@ version = {attr = "flask.__version__"}
 
 [tool.pytest.ini_options]
 testpaths = ["tests"]
-filterwarnings = ["error"]
+filterwarnings = [
+    "error",
+    # change in Python 3.12 alpha causes warning from inside pytest
+    "ignore:onerror argument:DeprecationWarning",
+]
 
 [tool.coverage.run]
 branch = true