Only codegen for tests once per pytest invocation

tests/codegen/test_rpc.py

@@ -3,21 +3,29 @@
 
 import pytest
 
+import importlib
 from replit_river.client import Client
 from replit_river.codegen.client import schema_to_river_client_codegen
 from tests.common_handlers import basic_rpc_method
 
 
-@pytest.mark.asyncio
-@pytest.mark.parametrize("handlers", [{**basic_rpc_method}])
-async def test_basic_rpc(client: Client) -> None:
+@pytest.fixture(scope="session", autouse=True)
+def generate_rpc_client() -> None:
+    import tests.codegen.rpc.generated
+
     shutil.rmtree("tests/codegen/rpc/generated")
     schema_to_river_client_codegen(
         "tests/codegen/rpc/schema.json",
         "tests/codegen/rpc/generated",
         "RpcClient",
         True,
     )
+    importlib.reload(tests.codegen.rpc.generated)
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("handlers", [{**basic_rpc_method}])
+async def test_basic_rpc(client: Client) -> None:
     from tests.codegen.rpc.generated import RpcClient
 
     res = await RpcClient(client).test_service.rpc_method(