📝 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/response_model/tutorial001_py310.py

@@ -0,0 +1,44 @@
+from fastapi import FastAPI
+from sqlmodel import Field, Session, SQLModel, create_engine, select
+
+
+class Hero(SQLModel, table=True):
+    id: int | None = Field(default=None, primary_key=True)
+    name: str = Field(index=True)
+    secret_name: str
+    age: int | None = Field(default=None, index=True)
+
+
+sqlite_file_name = "database.db"
+sqlite_url = f"sqlite:///{sqlite_file_name}"
+
+connect_args = {"check_same_thread": False}
+engine = create_engine(sqlite_url, echo=True, connect_args=connect_args)
+
+
+def create_db_and_tables():
+    SQLModel.metadata.create_all(engine)
+
+
+app = FastAPI()
+
+
+@app.on_event("startup")
+def on_startup():
+    create_db_and_tables()
+
+
+@app.post("/heroes/", response_model=Hero)
+def create_hero(hero: Hero):
+    with Session(engine) as session:
+        session.add(hero)
+        session.commit()
+        session.refresh(hero)
+        return hero
+
+
+@app.get("/heroes/", response_model=list[Hero])
+def read_heroes():
+    with Session(engine) as session:
+        heroes = session.exec(select(Hero)).all()
+        return heroes

docs_src/tutorial/fastapi/response_model/tutorial001_py39.py

@@ -0,0 +1,46 @@
+from typing import Optional
+
+from fastapi import FastAPI
+from sqlmodel import Field, Session, SQLModel, create_engine, select
+
+
+class Hero(SQLModel, table=True):
+    id: Optional[int] = Field(default=None, primary_key=True)
+    name: str = Field(index=True)
+    secret_name: str
+    age: Optional[int] = Field(default=None, index=True)
+
+
+sqlite_file_name = "database.db"
+sqlite_url = f"sqlite:///{sqlite_file_name}"
+
+connect_args = {"check_same_thread": False}
+engine = create_engine(sqlite_url, echo=True, connect_args=connect_args)
+
+
+def create_db_and_tables():
+    SQLModel.metadata.create_all(engine)
+
+
+app = FastAPI()
+
+
+@app.on_event("startup")
+def on_startup():
+    create_db_and_tables()
+
+
+@app.post("/heroes/", response_model=Hero)
+def create_hero(hero: Hero):
+    with Session(engine) as session:
+        session.add(hero)
+        session.commit()
+        session.refresh(hero)
+        return hero
+
+
+@app.get("/heroes/", response_model=list[Hero])
+def read_heroes():
+    with Session(engine) as session:
+        heroes = session.exec(select(Hero)).all()
+        return heroes