fix: better test case

tests/test_compat.py

@@ -88,25 +88,41 @@ def test_propagates_pydantic2_model_config():
         def __bool__(self):
             return False
 
+    class EmbeddedModel(BaseModel):
+        model_config = ConfigDict(arbitrary_types_allowed=True)
+        value: Union[str, Missing] = Missing()
+
     class Model(BaseModel):
         model_config = ConfigDict(
             arbitrary_types_allowed=True,
         )
         value: Union[str, Missing] = Missing()
+        embedded_model: EmbeddedModel = EmbeddedModel()
 
     @app.post("/")
-    def foo(req: Model) -> Union[str, None]:
-        return req.value or None
+    def foo(req: Model) -> Dict[str, Union[str, None]]:
+        return {
+            "value": req.value or None,
+            "embedded_value": req.embedded_model.value or None,
+        }
 
     client = TestClient(app)
 
     response = client.post("/", json={})
     assert response.status_code == 200, response.text
-    assert response.json() is None
+    assert response.json() == {
+        "value": None,
+        "embedded_value": None,
+    }
 
-    response2 = client.post("/", json={"value": "foo"})
+    response2 = client.post(
+        "/", json={"value": "foo", "embedded_model": {"value": "bar"}}
+    )
     assert response2.status_code == 200, response2.text
-    assert response2.json() == "foo"
+    assert response2.json() == {
+        "value": "foo",
+        "embedded_value": "bar",
+    }
 
 
 def test_is_bytes_sequence_annotation_union():