starter code for adding a spec file in https://github.com/Techtonica/curriculum/blob/master/javascript/event-recommender-part2.md

EventRecommenderSpec.js

describe("EventRecommender", () => {
  const EventRecommender = require('../app/EventRecommender');
  let er;

  beforeEach(() => {
    er = new EventRecommender();
  });

  describe("addEvent", () => {
    it("adds a new Event to the system", () => {
      er.addEvent("Change Me");
      expect(er.events.length).toEqual(1);
      expect(er.events[0].title).toEqual("Change Me"); // what are some other things you can test?
    });
  });
  
  describe("addUser", () => {
    it("adds a new User to the system", () => {
      er.addUser("Change Me");
      expect(er.user.length).toEqual(1);
    });
  });
    
  describe("saveUserEvent", () => {
    it("adds an event to a user's personal event array", () => {
      er.addEvent("Make a new event");
      er.addUser("Make a new user");
      er.saveUserEvent("event", "user"); // change these to match your method signature
      expect(er.user.personalEvents.length).toEqual(1);
    });
  });
    
  describe("deleteUser", () => {
    it("removes a User from the system", () => {
      er.addUser("Make a new user here that you will delete later");
      er.deleteUser("Change Me");
      expect(er.user.length).toEqual(0);
    });
  });
    
  describe("deleteEvent", () => {
    it("removes the event from the system", () => {
      er.addEvent("A new event that you will delete later");
      er.deleteEvent("Change Me");
      expect(er.events.length).toEqual(0);
    });
  });
});