Hypercubed/cypress-page-object-pattern

Cypress Page Object Pattern Example

Cypress Page Object Pattern Example

This repo is a test/demonstration of three patterns and one anti-pattern for using Page-Objects (reference needed) or Page-Object-like testing patterns in Cypress.

Disclaimer: I am a JavaScript developer not an experienced e2e tester and new to Cypress myself.. so take it for what it is.

(Anti-)Patterns

Pattern A: The anti-pattern

Pattern A is an anti-pattern. When navigating from page to page within a single test flow, new page instances are created from page classes each time. This breaks the Cypress' internal async queuing and necessitates excessive use of .thens and/or callbacks.

Do not do this!

Page Module

import BasePage from './BasePageClass';
import QueryPage from './NavigationMenuClass';

export default class MainPage extends BasePage  {
  constructor() {
    super();
    this.mainElement = 'body > .banner';
  }

  verifyElements() {
    return cy.get(this.mainElement).find('.container h1').should('be.visible').then(() => {
      return this.navMenu.verifyElements();
    });
  }

  switchToQueryingPage() {
    return this.navMenu.switchToQueryingPage().then(() => {
      cy.log('==> Finding Query Page');
      const queryPage = new QueryPage();
      return queryPage.verifyElements()
        .then(() => queryPage);
    });
  }
};

Integration Test

import MainPage from '../support/pageObjects-A/MainPageClass';

describe('Page Object Pattern - A', () => {
  context('Querying', () => {
    let mainPage;

    beforeEach(() => {
      return cy.visit('https://example.cypress.io/')
        .get('body > .banner h1').should('be.visible').then(() => {
          mainPage = new MainPage();
          return mainPage.verifyElements();
        });
    });

    it('cy.get() - query DOM elements', () => {
      mainPage.switchToQueryingPage();
    });
  });
});

Pattern B: page classes

In Pattern B we keep the page class definitions, which may be useful for inheritance, but each page class module exports a single page object instance of the class. These instances can be used throughout the testing and within other classes.

Do this if you must have page classes and inheritance.

Page Module

import { BasePage } from './BasePageClass'
import { navMenu } from './NavigationMenuClass';
import { queryPage } from './QueryPageClass';

export class MainPage extends BasePage  {
  constructor() {
    super();
    this.mainElement = 'body > .banner';
  }

  verifyElements() {
    super.verifyElements();
    cy.get(this.mainElement).find('.container h1').should('be.visible');
  }

  switchToQueryingPage() {
    navMenu.switchToQueryingPage();
    queryPage.verifyElements();
  }
};

export const mainPage = new MainPage();

Integration Test

import { mainPage } from '../support/pageObjects-B/MainPageClass';

describe('Page Object Pattern - B', () => {
  context('Querying', () => {
    beforeEach(() => {
      cy.visit('https://example.cypress.io/')
        .get('body > .banner h1').should('be.visible');
      mainPage.verifyElements();
    });

    it('cy.get() - query DOM elements', () => {
      mainPage.switchToQueryingPage();
    });
  });
});

Pattern C: page objects

In Pattern C we eliminate classes entirely. Instead each page module creates and exports single page object instance. These instances are used in the same way as pattern B.

Do this if you don't need page classes and inheritance.

Page Module

import { navMenu } from './navigationMenu';
import { queryPage } from './queryPage';

const bannerElement = 'body > .banner';

export const mainPage = {
  verifyElements() {
    cy.get(bannerElement).find('.container h1').should('be.visible');
    navMenu.verifyElements();
  },
  switchToQueryingPage() {
    navMenu.switchToQueryingPage();
    queryPage.verifyElements();
  }
}

Integration Test

import { mainPage } from '../support/pageObjects-C/mainPage';

describe('Page Object Pattern - C', () => {
  context('Querying', () => {
    beforeEach(() => {
      cy.visit('https://example.cypress.io/')
        .get('body > .banner h1').should('be.visible');
      mainPage.verifyElements();
    });

    it('cy.get() - query DOM elements', () => {
      mainPage.switchToQueryingPage();
    });
  });
});

Pattern D: page modules

In Pattern D we eliminate the objects themselves. Instead each page module creates and exports public functions. These public function can be imported and used in an almost identical way the as pattern B and C.

Do this if you don't need page objects.

Page Module

import * as navMenu from './navigationMenu';
import * as queryPage from './queryPage';

const bannerElement = 'body > .banner';

export function verifyElements() {
  cy.get(bannerElement).find('.container h1').should('be.visible');
  navMenu.verifyElements();
}

export function switchToQueryingPage() {
  navMenu.switchToQueryingPage();
  queryPage.verifyElements();
}

Integration Test

import * as mainPage from '../support/pageObjects-D/mainPage';

describe('Page "Object" Pattern - D', () => {
  context('Querying', () => {
    beforeEach(() => {
      cy.visit('https://example.cypress.io/')
        .get('body > .banner h1').should('be.visible');
      mainPage.verifyElements();
    });

    it('cy.get() - query DOM elements', () => {
      mainPage.switchToQueryingPage();
    });
  });
});

Pattern E: Cypress commands (to be done)

In Pattern D we (will) show how to emulate page object pattern using cypress commands. To be completed later, contributions welcome.