Test framework for Node.js middleware (Koa and Express)
This library aims to reduce amount of boilerplate you need to write in order to test middleware.
It is testing framework-agnostic and allows you to use any tool for managing test suites and assertions;
middleware-testlab takes care of instantiating and shutting down application, controller and middleware instances.
Install middleware-testlab as an npm module and save it to your package.json file as a development dependency:
npm install middleware-testlab --save-devOnce installed it can now be referenced by simply calling require('middleware-testlab');
If you want to access Typescript version of a library, call ``import { /desired imports/} from middleware-testlab/index-ts
import request from 'supertest'
import { newExpressApp, DEFAULT_ENDPOINT } from 'middleware-testlab'
import { Request, Response } from 'express'
import { expressMiddleware } from './expressRequestMutationMiddleware'
describe('mutation middleware', () => {
describe('express', () => {
it('happy path', async () => {
// Arrange: Instantiate app
const app = newExpressApp({
// Arrange: Pass middleware under test
routeMiddleware: [expressMiddleware()],
transformedRequestAssertors: [
(req: Request): void => {
// Assert: Check middleware execution results inside endpoint handler
// @ts-ignore
expect(req.logger).toMatchSnapshot()
}
]
// This is optional, if no handler is passed, default handler will return 204
handler: (req: Request, res: Response, next: Function) => {
res.status(204).send()
next()
}
})
// Act: Send request for middleware to process
const response = await request(app).get(DEFAULT_ENDPOINT)
// Assert: Check response
expect(response.status).toEqual(201)
})
})
})
import { BaseContext } from 'koa'
import { newKoaApp, DEFAULT_ENDPOINT, KoaServerManagerJest } from 'middleware-testlab'
import { koaMiddleware } from './koaRequestMutationMiddleware'
describe('mutation middleware', () => {
describe('koa', () => {
const server = new KoaServerManagerJest()
server.stopAfterEach()
it('happy path', async () => {
// Arrange: Instantiate app
const app = newKoaApp({
// Arrange: Pass middleware under test
routerMiddleware: [koaMiddleware()],
transformedRequestAssertors: [
(ctx: BaseContext): void => {
// Assert: Check middleware execution results inside endpoint handler
expect(ctx.logger).toMatchSnapshot()
}
]
// This is optional, if no handler is passed, default handler will return 204
handler: (ctx: BaseContext, next: Function) => {
ctx.status = 204
next()
}
})
server.start(app)
// Act: Send request for middleware to process
const response = await server.request().get(DEFAULT_ENDPOINT)
// Assert: Check response
expect(response.status).toEqual(201)
})
})
})
Note that since SuperTest does not support passing instance of a Koa app directly to
its agent, you need to wrap application instance into Node.js server. You can use
KoaServerManager* helper classes for that, or invoke const server = app.listen(port) yourself.
