页面对象模型

介绍

大型测试套件可以通过结构化来优化编写和维护的便捷性。页面对象模型（Page Object Model）是结构化测试套件的一种方法。

页面对象表示你 web 应用程序的一部分。例如，一个电子商务应用可能有首页、列表页和结账页。每个页面都可以通过页面对象模型来表示。

页面对象通过创建一个更高层次的 API 来简化编写，适应你的应用需求，并通过将元素选择器集中在一个地方来简化维护，避免代码重复，从而实现代码复用。

实现

我们将创建一个 PlaywrightDevPage 辅助类来封装在 playwright.dev 页面上的常见操作。内部将使用 page 对象模型。

TypeScript
JavaScript
Library

playwright-dev-page.ts

import { expect, type Locator, type Page } from '@playwright/test';

export class PlaywrightDevPage {
  readonly page: Page;
  readonly getStartedLink: Locator;
  readonly gettingStartedHeader: Locator;
  readonly pomLink: Locator;
  readonly tocList: Locator;

  constructor(page: Page) {
    this.page = page;
    this.getStartedLink = page.locator('a', { hasText: 'Get started' });
    this.gettingStartedHeader = page.locator('h1', { hasText: 'Installation' });
    this.pomLink = page.locator('li', {
      hasText: 'Guides',
    }).locator('a', {
      hasText: 'Page Object Model',
    });
    this.tocList = page.locator('article div.markdown ul > li > a');
  }

  async goto() {
    await this.page.goto('https://playwright.dev');
  }

  async getStarted() {
    await this.getStartedLink.first().click();
    await expect(this.gettingStartedHeader).toBeVisible();
  }

  async pageObjectModel() {
    await this.getStarted();
    await this.pomLink.click();
  }
}

playwright-dev-page.js

const { expect } = require('@playwright/test');

exports.PlaywrightDevPage = class PlaywrightDevPage {

  /**
   * @param {import('@playwright/test').Page} page
   */
  constructor(page) {
    this.page = page;
    this.getStartedLink = page.locator('a', { hasText: 'Get started' });
    this.gettingStartedHeader = page.locator('h1', { hasText: 'Installation' });
    this.pomLink = page.locator('li', {
      hasText: 'Guides',
    }).locator('a', {
      hasText: 'Page Object Model',
    });
    this.tocList = page.locator('article div.markdown ul > li > a');
  }

  async goto() {
    await this.page.goto('https://playwright.dev');
  }

  async getStarted() {
    await this.getStartedLink.first().click();
    await expect(this.gettingStartedHeader).toBeVisible();
  }

  async pageObjectModel() {
    await this.getStarted();
    await this.pomLink.click();
  }
};

models/PlaywrightDevPage.js

class PlaywrightDevPage {
  /**
   * @param {import('playwright').Page} page
   */
  constructor(page) {
    this.page = page;
    this.getStartedLink = page.locator('a', { hasText: 'Get started' });
    this.gettingStartedHeader = page.locator('h1', { hasText: 'Installation' });
    this.pomLink = page.locator('li', {
      hasText: 'Playwright Test',
    }).locator('a', {
      hasText: 'Page Object Model',
    });
    this.tocList = page.locator('article div.markdown ul > li > a');
  }
  async getStarted() {
    await this.getStartedLink.first().click();
    await expect(this.gettingStartedHeader).toBeVisible();
  }

  async pageObjectModel() {
    await this.getStarted();
    await this.pomLink.click();
  }
}
module.exports = { PlaywrightDevPage };

现在我们可以在测试中使用 PlaywrightDevPage 类了。

TypeScript
JavaScript
Library

example.spec.ts

import { test, expect } from '@playwright/test';
import { PlaywrightDevPage } from './playwright-dev-page';

test('getting started should contain table of contents', async ({ page }) => {
  const playwrightDev = new PlaywrightDevPage(page);
  await playwrightDev.goto();
  await playwrightDev.getStarted();
  await expect(playwrightDev.tocList).toHaveText([
    `How to install Playwright`,
    `What's Installed`,
    `How to run the example test`,
    `How to open the HTML test report`,
    `Write tests using web first assertions, page fixtures and locators`,
    `Run single test, multiple tests, headed mode`,
    `Generate tests with Codegen`,
    `See a trace of your tests`
  ]);
});

test('should show Page Object Model article', async ({ page }) => {
  const playwrightDev = new PlaywrightDevPage(page);
  await playwrightDev.goto();
  await playwrightDev.pageObjectModel();
  await expect(page.locator('article')).toContainText('Page Object Model is a common pattern');
});

example.spec.js

const { test, expect } = require('@playwright/test');
const { PlaywrightDevPage } = require('./playwright-dev-page');

test('getting started should contain table of contents', async ({ page }) => {
  const playwrightDev = new PlaywrightDevPage(page);
  await playwrightDev.goto();
  await playwrightDev.getStarted();
  await expect(playwrightDev.tocList).toHaveText([
    `How to install Playwright`,
    `What's Installed`,
    `How to run the example test`,
    `How to open the HTML test report`,
    `Write tests using web first assertions, page fixtures and locators`,
    `Run single test, multiple tests, headed mode`,
    `Generate tests with Codegen`,
    `See a trace of your tests`
  ]);
});

test('should show Page Object Model article', async ({ page }) => {
  const playwrightDev = new PlaywrightDevPage(page);
  await playwrightDev.goto();
  await playwrightDev.pageObjectModel();
  await expect(page.locator('article')).toContainText('Page Object Model is a common pattern');
});

example.spec.js

const { PlaywrightDevPage } = require('./playwright-dev-page');

// In the test
const page = await browser.newPage();
await playwrightDev.goto();
await playwrightDev.getStarted();
await expect(playwrightDev.tocList).toHaveText([
  `How to install Playwright`,
  `What's Installed`,
  `How to run the example test`,
  `How to open the HTML test report`,
  `Write tests using web first assertions, page fixtures and locators`,
  `Run single test, multiple tests, headed mode`,
  `Generate tests with Codegen`,
  `See a trace of your tests`
]);