diff --git a/tests/hydra/my_app.py b/tests/hydra/my_app.py
index dca19dc0bdc1..3ee28f98d788 100644
--- a/tests/hydra/my_app.py
+++ b/tests/hydra/my_app.py
@@ -38,6 +38,7 @@ def my_app(cfg):
     print(OmegaConf.to_yaml(cfg))
     # Get dataset_name.
     dataset_name = cfg.dataset_name
+    assert isinstance(dataset_name, str), f"dataset_name must be a str, got {type(dataset_name)}"
 
 
 if __name__ == "__main__":
diff --git a/tests/hydra/test_hydra_runner.py b/tests/hydra/test_hydra_runner.py
index 11c3f3dc6601..2b05a8c8b070 100644
--- a/tests/hydra/test_hydra_runner.py
+++ b/tests/hydra/test_hydra_runner.py
@@ -78,6 +78,16 @@ def test_config2_invalid(self):
             # Run the call as subprocess.
             subprocess.check_call(call, shell=True, stdout=sys.stdout, stderr=sys.stdout)
 
+    @pytest.mark.unit
+    def test_passthrough_config(self):
+        """Test calling my_app directly with a DictConfig (cfg_passthrough path)."""
+        from omegaconf import OmegaConf
+
+        from tests.hydra.my_app import my_app
+
+        cfg = OmegaConf.create({"dataset_name": "passthrough_test"})
+        my_app(cfg)
+
     @pytest.mark.integration
     def test_config2_filepath_schema(self):
         """ "Test injection of valid config2 - using namepath with schema is prohibited."""