Jest Testing of Redis Service - node.js

Question

I have a number of services in my Nodejs repo that uses Redis. I'm trying to improve the quality of my development and therefore am starting to implement Jest testing. However, I cannot get the Jest tests to connect to the (test) Redis database during testing.
I've tried using a continually running Redis server on the CI/CD (Jenkins) server and I have tried using this library "Redis-Memory-Server" which is meant to create a Redis server instance during testing. I've spent many hours this week trying to fix this issue and have no idea why it's happening.
Any help is greatly appreciated.
Redis Management File
// Redis database module for Unseen Games
const redis = require('redis');
const { promisifyAll } = require('bluebird');
const _ = require('lodash');
promisifyAll(redis);
//Contains all the redis clients currently made
var event_status = "unconnected";
var timeout_cleared = false;
const clients: any = {};
let connectionTimeout;
function throwTimeoutError() {
connectionTimeout = setTimeout(() => {
throw new Error('Redis connection failed');
}, 10000);
}
function instanceEventListenersRedis({ conn }) {
conn.on('connect', () => {
// console.log('CacheStore - Connection status: connected');
event_status = "connected";
timeout_cleared = false;
clearTimeout(connectionTimeout);
});
conn.on('ready', () => {
event_status = "ready";
// console.log('CacheStore - Connection status: ready');
})
conn.on('end', () => {
event_status = "disconnected";
// console.log('CacheStore - Connection status: disconnected');
//TODO: The below code should stop Jest from hanging when testing the code, but doesn't, fix?
// if(!timeout_cleared) {
// throwTimeoutError();
// }
});
conn.on('reconnecting', () => {
event_status = "reconnecting";
// console.log('CacheStore - Connection status: reconnecting');
clearTimeout(connectionTimeout);
});
conn.on('error', (err) => {
event_status = "error";
// console.log('CacheStore - Connection status: error ', { err });
throwTimeoutError();
});
}
export const redisInit = async () => {
if(process.env.BALENA==="1" || process.env.DEVICE === "local"){
const cacheInstance = redis.createClient(process.env.REDIS_URL);
clients.cacheInstance = cacheInstance;
instanceEventListenersRedis({ conn: cacheInstance });
} else if(process.env.DEVICE =="demo") {
event_status = "connecting"
const cacheInstance = redis.createClient({host: process.env.REDIS_HOST, port: process.env.REDIS_PORT});
clients.cacheInstance = cacheInstance;
instanceEventListenersRedis({ conn: cacheInstance });
} else {
throw Error;
}
};
export const redisCheckConnection = () => {
if(process.env.REDIS == "true") {
return event_status;
} else {
return "readyo";
}
}
export const redisGetClients = () => clients;
export const redisCloseConnections = () => {
timeout_cleared = true;
_.forOwn(clients, (conn) => conn.quit());
}
jest.config.js
module.exports = {
preset: 'ts-jest',
testEnvironment: 'node',
setupFiles: ['dotenv/config'],
transform: {}
};
process.env = Object.assign(process.env, {
REDIS: 'true',
DEVICE: 'demo'
});