Make tests more end-to-end to keep code coverage high.

tests/forward_reference_type.py

@@ -2,7 +2,7 @@ from pydantic import BaseModel
 
 
 def forwardref_method(input: "ForwardRef") -> "ForwardRef":
-    return ForwardRef()
+    return ForwardRef(x=input.x + 1)
 
 
 class ForwardRef(BaseModel):

tests/test_wrapped_method_forward_reference.py

@@ -1,6 +1,7 @@
 import functools
 
 from fastapi import FastAPI
+from fastapi.testclient import TestClient
 
 from .forward_reference_type import forwardref_method
 
@@ -21,5 +22,10 @@ def test_wrapped_method_type_inference():
     references.
     """
     app = FastAPI()
-    app.get("/endpoint")(passthrough(forwardref_method))
-    app.get("/endpoint2")(passthrough(passthrough(forwardref_method)))
+    client = TestClient(app)
+    app.post("/endpoint")(passthrough(forwardref_method))
+    app.post("/endpoint2")(passthrough(passthrough(forwardref_method)))
+    with client:
+        response = client.post("/endpoint", json={"input": {"x": 0}})
+        response2 = client.post("/endpoint2", json={"input": {"x": 0}})
+    assert response.json() == response2.json() == {"x": 1}