tests: update env.py and conftest so tests use unique databases (#3654)

* Refactor Alembic environment script to simplify database connection logic and remove unused imports

* Refactor test client fixture to use TemporaryDirectory and UUID for database path

* Add `reload_engine` method to reinitialize the database engine

* Add cleanup steps to test fixtures to ensure proper resource management

- Added cleanup steps to various pytest fixtures to ensure temporary directories, database entries, and other resources are properly cleaned up after tests.
- Modified fixtures to use `yield` for better resource management.
- Ensured database connections are closed and tables are dropped after tests.
- Improved temporary directory handling with context managers.

* Add unit test to verify return type of list_flows method in custom component

* Refactor tests in `test_custom_component.py` to remove unused imports and fixtures, and update existing fixtures for consistency.

* Add debug checks for user existence in `test_user_waiting_for_approval` test

* Fix import order and add flow_id validation in transaction handling

- Corrected the import order in `utils.py`.
- Added validation for `flow_id` in the transaction handling logic to ensure it is set correctly.

* Add function to delete transactions by flow ID in CRUD module

* Add cleanup for transactions and vertex builds in test teardown

- Introduced `_delete_transactions_and_vertex_builds` function to remove transactions and vertex builds associated with a user.
- Updated `user` fixture to call the new cleanup function before deleting the user.

* Refactor flow_id assignment logic in `utils.py` to improve readability and correctness

* [autofix.ci] apply automated fixes

* Refactor test to use pytest's tmp_path fixture for temporary directory creation

* Convert `test_user_waiting_for_approval` to an async test function

---------

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

src/backend/tests/unit/test_custom_component.py

@@ -1,7 +1,6 @@
 import ast
 import types
 from textwrap import dedent
-from uuid import uuid4
 
 import pytest
 from langchain_core.documents import Document
@@ -10,8 +9,6 @@ from langflow.custom import Component, CustomComponent
 from langflow.custom.code_parser.code_parser import CodeParser, CodeSyntaxError
 from langflow.custom.custom_component.base_component import BaseComponent, ComponentCodeNullError
 from langflow.custom.utils import build_custom_component_template
-from langflow.services.database.models.flow import FlowCreate
-from langflow.services.settings.feature_flags import FEATURE_FLAGS
 
 
 @pytest.fixture
@@ -460,9 +457,8 @@ def test_build_config_no_code():
 
 
 @pytest.fixture
-def component(client, active_user):
-    return CustomComponent(
-        user_id=active_user.id,
+def component():
+    yield CustomComponent(
         field_config={
             "fields": {
                 "llm": {"type": "str"},
@@ -473,41 +469,6 @@ def component(client, active_user):
     )
 
 
-@pytest.fixture(scope="session")
-def test_flow(db):
-    flow_data = {
-        "nodes": [{"id": "1"}, {"id": "2"}],
-        "edges": [{"source": "1", "target": "2"}],
-    }
-
-    # Create flow
-    flow = FlowCreate(id=uuid4(), name="Test Flow", description="Fixture flow", data=flow_data)
-
-    # Add to database
-    db.add(flow)
-    db.commit()
-
-    yield flow
-
-    # Clean up
-    db.delete(flow)
-    db.commit()
-
-
-@pytest.fixture(scope="session")
-def db(app):
-    # Setup database for tests
-    yield app.db
-
-    # Teardown
-    app.db.drop_all()
-
-
-def test_list_flows_return_type(component):
-    flows = component.list_flows()
-    assert isinstance(flows, list)
-
-
 def test_build_config_return_type(component):
     config = component.build_config()
     assert isinstance(config, dict)
@@ -539,19 +500,11 @@ def test_build_config_field_value_keys(component):
     assert all("type" in value for value in field_values)
 
 
-def test_custom_component_multiple_outputs(code_component_with_multiple_outputs, active_user):
-    frontnd_node_dict, _ = build_custom_component_template(code_component_with_multiple_outputs, active_user.id)
+def test_custom_component_multiple_outputs(code_component_with_multiple_outputs):
+    frontnd_node_dict, _ = build_custom_component_template(code_component_with_multiple_outputs)
     assert frontnd_node_dict["outputs"][0]["types"] == ["Text"]
 
 
-def test_feature_flags_add_toolkit_output(active_user, code_component_with_multiple_outputs):
-    frontnd_node_dict, _ = build_custom_component_template(code_component_with_multiple_outputs, active_user.id)
-    len_outputs = len(frontnd_node_dict["outputs"])
-    FEATURE_FLAGS.add_toolkit_output = True
-    frontnd_node_dict, _ = build_custom_component_template(code_component_with_multiple_outputs, active_user.id)
-    assert len(frontnd_node_dict["outputs"]) == len_outputs + 1
-
-
 def test_custom_component_subclass_from_lctoolcomponent():
     # Import LCToolComponent and create a subclass
     code = dedent("""