Testing express middleware

I'm trying to write a test for simple middlware function I'm implementing.​// middlewareconst Joi = require('joi');​module.exports = (req, res, next) => {​const schema = Joi.object().keys({memberId: Joi.string().required()});​Joi.validate(req.body, schema, (err, value) => {if (err) {return next(err);}​next();});};​// passing test when memberId is OKtest("Schema should be valid", () => {​const req = {body: {memberId: "MID 12345"}};​const res = {}​const next = jest.fn();​validateSchema(req, res, next);​expect(next).toHaveBeenCalled();expect(next).toHaveBeenCalledTimes(1);expect(next).toBeCalledWith();});​I'm having issues writing failing test when memberId param is not found. For example:const req = {body: {blahId: "MID 12345"}};​I would like to write a test to confirm that next(err) has been called but I'm having no luck connecting the dots: For example,test("Schema should be valid", () => {​const req = {body: {fakeId: "MID 12345"}};​const res = {}​const next = jest.fn();​validateSchema(req, res, next);​expect(next).toHaveBeenCalled();expect(next).toHaveBeenCalledTimes(1);// How do I test if next has been called with err and how could I assert against property of err object.expect(next).toBeCalledWith(err);});​​If I change my middleware to call​next(err.details)​then​expect(next).toBeCalledWith([{ "context": { "key": "memberId", "label": "memberId" }, "message": "\"memberId\" is required", "path": ["memberId"], "type": "any.required" }]);​works fine however this doesn't seem/feel right.​I also have a global error handler that looks like this​app.use((err, req, res, next) => {​console.log(err);​if (err.name === 'UnauthorizedError') {return res.status(401).send();}​res.status(err.code || 500).send(err);});​Thank you.

Submitted November 25, 2018 at 07:15PM by roboctocat