Sept 12 2023

Setting up jest, supertest in a typescript node.Js app

express

typescript

node

node.js

jest

supertest

Setting up jest, supertest in a typescript node.Js app

By the end of this post you will know how to setup supertest and jest for a node.Js typescript project (Sept 2023).

install the following packages (9):
Making a basic express app
Writing a basic test
Conclusion

install the following packages (9):

install the following dev dependencies

//run in terminal
npm i -D typescript ts-jest jest @types/express @types/jest @types/node @types/supertest nodemon supertest typescript

to create a jest.config.js file run the following in the terminal:

//run in terminal
npx ts-jest config:init

to create a tsconfig.json run the following command in the terminal

tsc --init

add the following to the tsconfig.json file to exclude the test files.

{
  "compilerOptions": {
   // your options (configure these)
  },
  "include": [
    "./src/**/*.ts"
  ],
  "exclude": [
    "./src/**/*.test.*"
  ]
}

Making a basic express app

now install express and then make a folder called src and inside files called app.ts and server.ts and routes.ts. In app.ts write

//app.ts
import express from "express"
import { generalGET } from "./routes"
function createApp (){
    const app = express()

app.get("/",generalGET)


    return app
}

export default createApp

in routes.ts write

import { Request, Response } from "express"

export const generalGET = (req:Request,res:Response)=>{
    res.status(200)
    res.json({success:true})
}

and in server.ts write

import createApp from "./app"

const app = createApp()
app.listen(5000,()=>{console.log("server is running on port 5000")})

add the following commands to package.json

// in scripts section
"testAll":"jest --watchAll",
    "build":"tsc",
    "start":"node dist/server.js",
    "server":"nodemon src/server.ts"

Writing a basic test

update the typescript config file tscongig.json outDir to ./dist. Also make a file called app.test.ts in /src and inside put the code.

import request from "supertest"
import createApp from "../app"
const app = createApp()
describe('route / method GET',()=>{
   describe('when the route is called',()=>{
    it('should respond with 200 status and json body',async()=>{
        const response = await request(app).get("/")
        expect(response.status).toBe(200)
        expect(response.headers['content-type']).toEqual(expect.stringContaining('json'))
   })
   })
})

now run npm run testAll to run the test.

Conclusion

Thank you for reading. This blog has explained the basic setup for testing a node.Js typescript application using supertest and jest as of September 2023.

You have reached the end of this post. Thank you for reading!

Setting up jest, supertest in a typescript node.Js app

Setting up jest, supertest in a typescript node.Js app

Table of Contents

install the following packages (9):

Making a basic express app

Writing a basic test

Conclusion