CODEWITHSUNDEEP
javascriptnode.jsredisjestjs
Mohamed Ali
Mohamed Ali

Reputation: 782

How to write test for when redisClient errors using jest

I am stuck on writing a unit test for when the redisClient fails for the createClient call. Any idea on how I can write this. Below you will find what I have so far.

const asyncRedis = require("async-redis");

class redis {
    constructor(redisHost, redisPort) {
        this.redisHost = redisHost;
        this.redisPort = redisPort;
    }

    async init() {
        try {
            this.redisClient = asyncRedis.createClient({
                port: this.redisPort, 
                host: this.redisHost
            });
        } catch(error) {
            console.log(`Error creating client due to: ${error}`)
        }
    }
}

module.exports =  redis;

redis-test.js

test('init on error', async () => {
        jest.mock('../../src/redis/redis')
        const redis = require('../../src/redis/Redis');

        redis.mockImplementation(() => {
            return {
                init: jest.fn(() => { throw new Error(); }
            )};
        })

        expect(await redis.init()).toThrowError(Error());

    })

Upvotes: 0

Views: 1256

Answers (1)

usuario
usuario

Reputation: 2467

You are mocking your code, you should be mocking the async-redis library code.

You need to mock the createClient method to always throw an error. So that you can check your catch flow is executed.

This part, you got it right jest.fn(() => { throw new Error(); }, always return an error.

I am no expert in NodeJS, sorry I am not able to provide detailed source code.

Upvotes: 1

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