For the past few years, I have been developing an ExpressJS server application for internal use at my workplace. This application serves as a clinical decision support tool utilized in various hospitals. As the application has grown significantly in size, making changes to it has become quite challenging.
Having started coding before the era of test suites, I now understand the importance of using them. After considering various options, I have decided to go with Jest. However, I encountered an issue where I had to separate the server definition and the app entry point into different files to allow for importing just the server components in tests. To address this, I refactored my code, resulting in the creation of both index.js and server.js files.
The main challenge I am facing is related to the numerous imports in my server file, especially references to middleware functions and a file named appDB.js, which loads a significant amount of Sequelize data (using Tedious for MSSQL). While my initial tests are passing, I am encountering errors stating that Jest attempted imports after the environment was torn down, leading to issues with Sequelize functionality.
In the server.js file, I import the appDB.js file (containing the Sequelize references) to create the main tables of the application using seq.sync. Additionally, I include the session table definition for middleware requirements and load a permissions hierarchy from the database as needed.
I am seeking suggestions on how to refactor this setup to prevent Jest from throwing errors. I assume that once these errors are resolved, I should consider 'mocking' some DB functionality unless directly testing the DB. Most examples of utilizing Jest with a DB that I have come across focus on MongoDB rather than Sequelize and do not account for middleware reliant on database information.
Below are snippets from my files:
server.js (defines the server)-
// Code snippet showcasing multiple imports and server setup
index.js (Program entry file)-
// Code snippet indicating program initialization and server connection
appDB.js (Includes model files and defines relationships)-
// Code snippet illustrating database model setups and relationships
server.test.js (First test file)-
import { normalizePort } from './server';
// Sample test case using Jest to test port normalization