✅ 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>

tests/test_tutorial/test_debugging/test_tutorial001.py

@@ -0,0 +1,64 @@
+import importlib
+import runpy
+import sys
+import unittest
+
+import pytest
+from fastapi.testclient import TestClient
+
+MOD_NAME = "docs_src.debugging.tutorial001_py39"
+
+
+@pytest.fixture(name="client")
+def get_client():
+    mod = importlib.import_module(MOD_NAME)
+    client = TestClient(mod.app)
+    return client
+
+
+def test_uvicorn_run_is_not_called_on_import():
+    if sys.modules.get(MOD_NAME):
+        del sys.modules[MOD_NAME]  # pragma: no cover
+    with unittest.mock.patch("uvicorn.run") as uvicorn_run_mock:
+        importlib.import_module(MOD_NAME)
+    uvicorn_run_mock.assert_not_called()
+
+
+def test_get_root(client: TestClient):
+    response = client.get("/")
+    assert response.status_code == 200
+    assert response.json() == {"hello world": "ba"}
+
+
+def test_uvicorn_run_called_when_run_as_main():  # Just for coverage
+    if sys.modules.get(MOD_NAME):
+        del sys.modules[MOD_NAME]
+    with unittest.mock.patch("uvicorn.run") as uvicorn_run_mock:
+        runpy.run_module(MOD_NAME, run_name="__main__")
+
+    uvicorn_run_mock.assert_called_once_with(
+        unittest.mock.ANY, host="0.0.0.0", port=8000
+    )
+
+
+def test_openapi_schema(client: TestClient):
+    response = client.get("/openapi.json")
+    assert response.status_code == 200
+    assert response.json() == {
+        "openapi": "3.1.0",
+        "info": {"title": "FastAPI", "version": "0.1.0"},
+        "paths": {
+            "/": {
+                "get": {
+                    "summary": "Root",
+                    "operationId": "root__get",
+                    "responses": {
+                        "200": {
+                            "description": "Successful Response",
+                            "content": {"application/json": {"schema": {}}},
+                        },
+                    },
+                }
+            }
+        },
+    }