diff --git a/Makefile b/Makefile
index 41f538e..07c49ca 100644
--- a/Makefile
+++ b/Makefile
@@ -23,6 +23,8 @@ help: ## display help for this makefile
 .PHONY: codegen
 codegen: build-base ## Run codegen to convert the LinkML schema to a GQL API
 	$(docker_compose_run) $(BUILD_CONTAINER) api generate --schemafile ./schema/schema.yaml --output-prefix .
+	$(docker_compose_run) $(CONTAINER) black .
+	#$(docker_compose_run) $(CONTAINER) ruff check --fix  .
 
 .PHONY: rm-pycache
 rm-pycache: ## remove all __pycache__ files (run if encountering issues with pycharm debugger (containers exiting prematurely))
@@ -56,9 +58,6 @@ lint: ## Check for / fix bad linting
 .PHONY: codegen-tests
 codegen-tests: codegen  ## Run tests
 	$(docker_compose) up -d
-	$(docker_compose_run) -v platformics api generate --schemafile /app/schema/test_app.yaml --output-prefix /app
-	$(docker_compose_run) $(CONTAINER) black .
-	$(docker_compose_run) $(CONTAINER) ruff check --fix  .
 	$(docker_compose_run) $(CONTAINER) pytest
 
 ### GitHub Actions ###################################################
diff --git a/test_app/conftest.py b/test_app/conftest.py
index 0101966..2c48927 100644
--- a/test_app/conftest.py
+++ b/test_app/conftest.py
@@ -6,6 +6,7 @@
 import os
 import typing
 from typing import Optional
+from platformics.api.core.error_handler import HandleErrors
 
 import boto3
 import pytest
@@ -38,8 +39,6 @@
 from api.queries import Query
 import strawberry
 
-from main import app
-
 __all__ = [
     "gql_client",
     "moto_client",
@@ -119,12 +118,6 @@ async def async_db(sync_db: SyncDB, test_db: NoopExecutor) -> typing.AsyncGenera
     yield db
 
 
-@pytest_asyncio.fixture()
-async def api_test_schema(async_db: AsyncDB) -> FastAPI:
-    overwrite_api(app, async_db)
-    return app
-
-
 # When importing `gql_client`, it will use the `http_client` below, which uses the test schema
 @pytest_asyncio.fixture()
 async def http_client(api_test_schema: FastAPI) -> AsyncClient:
@@ -235,14 +228,25 @@ async def patched_session() -> typing.AsyncGenerator[AsyncSession, None]:
     api.dependency_overrides[get_s3_client] = patched_s3_client
 
 
+def raise_exception() -> str:
+    raise Exception("Unexpected error")
+
+# Subclass Query with an additional field to test Exception handling.
+@strawberry.type
+class MyQuery(Query):
+    @strawberry.field
+    def uncaught_exception(self) -> str:
+        # Trigger an AttributeException
+        return self.kaboom  # type: ignore
+
 @pytest_asyncio.fixture()
-async def api(async_db: AsyncDB) -> FastAPI:
+async def api_test_schema(async_db: AsyncDB) -> FastAPI:
     """
     Create an API instance using the real schema.
     """
     settings = APISettings.model_validate({})  # Workaround for https://github.com/pydantic/pydantic/issues/3753
     strawberry_config = get_strawberry_config()
-    schema = strawberry.Schema(query=Query, mutation=Mutation, config=strawberry_config)
+    schema = strawberry.Schema(query=MyQuery, mutation=Mutation, config=strawberry_config, extensions=[HandleErrors()])
     api = get_app(settings, schema, models)
     overwrite_api(api, async_db)
     return api