diff --git a/README.md b/README.md
index c8b6450..1a6d1cf 100644
--- a/README.md
+++ b/README.md
@@ -41,7 +41,7 @@ class Dependencies(Group):
 
 
 app = typer.Typer()
-container = modern_di.Container(groups=[Dependencies])
+container = modern_di.Container(groups=[Dependencies], validate=True)
 setup_di(app, container)
 
 
diff --git a/tests/conftest.py b/tests/conftest.py
index 24096ee..d5715ce 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -11,7 +11,7 @@
 @pytest.fixture
 def app() -> typing.Iterator[typer.Typer]:
     app_ = typer.Typer()
-    container = modern_di.Container(groups=[Dependencies])
+    container = modern_di.Container(groups=[Dependencies], validate=True)
     modern_di_typer.setup_di(app_, container=container)
     yield app_
     container.close_sync()