Add tests for OpenAPI callback tutorial

tests/test_tutorial/test_openapi_callbacks/test_tutorial002.py

@@ -0,0 +1,40 @@
+from unittest.mock import AsyncMock, patch
+
+from fastapi.testclient import TestClient
+
+from docs_src.openapi_callbacks.tutorial002_py310 import app
+
+client = TestClient(app)
+
+
+@patch("docs_src.openapi_callbacks.tutorial002_py310.httpx.AsyncClient.post")
+def test_process_passage(mock_post):
+    mock_post.return_value = AsyncMock()
+
+    response = client.post(
+        "/process-passage",
+        json={
+            "passage_topic": "FastAPI tutorial",
+            "callback_url": "http://testserver/callback",
+        },
+    )
+
+    assert response.status_code == 200
+    assert response.json() == {
+        "message": "Passage processing started"
+    }
+
+
+def test_callback():
+    response = client.post(
+        "/callback",
+        json={
+            "processed_passage": "FastAPI tutorial",
+            "status": "completed",
+        },
+    )
+
+    assert response.status_code == 200
+    assert response.json() == {
+        "received": True
+    }