import pytest from src import single_mock @pytest.fixture def mock_parameter_response(monkeypatch): def mockreturn(name): return "mock_value" monkeypatch.setattr(single_mock.parameters, "get_parameter", mockreturn) # Pass our fixture as an argument to all tests where we want to mock the get_parameter response def test_handler(mock_parameter_response): return_val = single_mock.handler({}, {}) assert return_val.get("message") == "mock_value"