Building Enterprise JavaScript Applications

Unit testing middleware

Next, we are going to test our middleware functions, starting with the checkEmptyPayload middleware. Like we did previously, move the middleware module into its own directory:

$ cd src/middlewares/ && \  mkdir check-empty-payload && \  mv check-empty-payload.js check-empty-payload/index.js && \  touch check-empty-payload/index.unit.test.js && \  cd ../../

Then, inside src/middlewares/check-content-type.js/index.unit.test.js, lay out the skeleton of our first test:

import assert from 'assert';import checkEmptyPayload from '.';describe('checkEmptyPayload', function () {  describe('When req.method is not one of POST, PATCH or PUT', function () {    it('should not modify res', function () { // Assert that `res` has not been modified ...