📝 Add source examples for Python 3.9 and 3.10 (#715)

* 📝 Add source examples for Python 3.9 and 3.10

* ✅ Add tests for new source examples for Python 3.9 and 3.10, still needs pytest markers

* ✅ Add tests for fastapi examples

* ✅ Update tests for FastAPI app testing, for Python 3.9 and 3.10, fixing multi-app testing conflicts

* ✅ Require Python 3.9 and 3.10 for tests

* ✅ Update tests with missing markers

docs_src/tutorial/fastapi/app_testing/tutorial001/test_extra_coverage.py

@@ -0,0 +1,38 @@
+from fastapi.testclient import TestClient
+from sqlalchemy import Inspector, inspect
+from sqlmodel import Session, create_engine
+
+from . import main as app_mod
+from .test_main import client_fixture, session_fixture
+
+assert client_fixture, "This keeps the client fixture used below"
+assert session_fixture, "This keeps the session fixture used by client_fixture"
+
+
+def test_startup():
+    app_mod.engine = create_engine("sqlite://")
+    app_mod.on_startup()
+    insp: Inspector = inspect(app_mod.engine)
+    assert insp.has_table(str(app_mod.Hero.__tablename__))
+
+
+def test_get_session():
+    app_mod.engine = create_engine("sqlite://")
+    for session in app_mod.get_session():
+        assert isinstance(session, Session)
+        assert session.bind == app_mod.engine
+
+
+def test_read_hero_not_found(client: TestClient):
+    response = client.get("/heroes/9000")
+    assert response.status_code == 404
+
+
+def test_update_hero_not_found(client: TestClient):
+    response = client.patch("/heroes/9000", json={"name": "Very-Rusty-Man"})
+    assert response.status_code == 404
+
+
+def test_delete_hero_not_found(client: TestClient):
+    response = client.delete("/heroes/9000")
+    assert response.status_code == 404