✅ Add missing tests for code examples (#14569)

Co-authored-by: Sebastián Ramírez <tiangolo@gmail.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Nils-Hero Lindemann <nilsherolindemann@proton.me>

docs_src/dataclasses_/tutorial002_py310.py

@@ -0,0 +1,25 @@
+from dataclasses import dataclass, field
+
+from fastapi import FastAPI
+
+
+@dataclass
+class Item:
+    name: str
+    price: float
+    tags: list[str] = field(default_factory=list)
+    description: str | None = None
+    tax: float | None = None
+
+
+app = FastAPI()
+
+
+@app.get("/items/next", response_model=Item)
+async def read_next_item():
+    return {
+        "name": "Island In The Moon",
+        "price": 12.99,
+        "description": "A place to be playin' and havin' fun",
+        "tags": ["breater"],
+    }