puppeteer/test/src/screenshot.spec.ts

/**
 * Copyright 2018 Google Inc. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import expect from 'expect';
import {
  getTestState,
  setupTestBrowserHooks,
  setupTestPageAndContextHooks,
} from './mocha-utils.js';
import {it} from './mocha-utils.js';

describe('Screenshots', function () {
  setupTestBrowserHooks();
  setupTestPageAndContextHooks();

  describe('Page.screenshot', function () {
    it('should work', async () => {
      const {page, server} = getTestState();

      await page.setViewport({width: 500, height: 500});
      await page.goto(server.PREFIX + '/grid.html');
      const screenshot = await page.screenshot();
      expect(screenshot).toBeGolden('screenshot-sanity.png');
    });
    it('should clip rect', async () => {
      const {page, server} = getTestState();

      await page.setViewport({width: 500, height: 500});
      await page.goto(server.PREFIX + '/grid.html');
      const screenshot = await page.screenshot({
        clip: {
          x: 50,
          y: 100,
          width: 150,
          height: 100,
        },
      });
      expect(screenshot).toBeGolden('screenshot-clip-rect.png');
    });
    it('should use scale for clip', async () => {
      const {page, server} = getTestState();

      await page.setViewport({width: 500, height: 500});
      await page.goto(server.PREFIX + '/grid.html');
      const screenshot = await page.screenshot({
        clip: {
          x: 50,
          y: 100,
          width: 150,
          height: 100,
          scale: 2,
        },
      });
      expect(screenshot).toBeGolden('screenshot-clip-rect-scale2.png');
    });
    it('should get screenshot bigger than the viewport', async () => {
      const {page, server} = getTestState();
      await page.setViewport({width: 50, height: 50});
      await page.goto(server.PREFIX + '/grid.html');
      const screenshot = await page.screenshot({
        clip: {
          x: 25,
          y: 25,
          width: 100,
          height: 100,
        },
      });
      expect(screenshot).toBeGolden('screenshot-offscreen-clip.png');
    });
    it('should run in parallel', async () => {
      const {page, server} = getTestState();

      await page.setViewport({width: 500, height: 500});
      await page.goto(server.PREFIX + '/grid.html');
      const promises = [];
      for (let i = 0; i < 3; ++i) {
        promises.push(
          page.screenshot({
            clip: {
              x: 50 * i,
              y: 0,
              width: 50,
              height: 50,
            },
          })
        );
      }
      const screenshots = await Promise.all(promises);
      expect(screenshots[1]!).toBeGolden('grid-cell-1.png');
    });
    it('should take fullPage screenshots', async () => {
      const {page, server} = getTestState();

      await page.setViewport({width: 500, height: 500});
      await page.goto(server.PREFIX + '/grid.html');
      const screenshot = await page.screenshot({
        fullPage: true,
      });
      expect(screenshot).toBeGolden('screenshot-grid-fullpage.png');
    });
    it('should run in parallel in multiple pages', async () => {
      const {server, context} = getTestState();

      const N = 2;
      const pages = await Promise.all(
        Array(N)
          .fill(0)
          .map(async () => {
            const page = await context.newPage();
            await page.goto(server.PREFIX + '/grid.html');
            return page;
          })
      );
      const promises = [];
      for (let i = 0; i < N; ++i) {
        promises.push(
          pages[i]!.screenshot({
            clip: {x: 50 * i, y: 0, width: 50, height: 50},
          })
        );
      }
      const screenshots = await Promise.all(promises);
      for (let i = 0; i < N; ++i) {
        expect(screenshots[i]).toBeGolden(`grid-cell-${i}.png`);
      }
      await Promise.all(
        pages.map(page => {
          return page.close();
        })
      );
    });
    it('should allow transparency', async () => {
      const {page, server} = getTestState();

      await page.setViewport({width: 100, height: 100});
      await page.goto(server.EMPTY_PAGE);
      const screenshot = await page.screenshot({omitBackground: true});
      expect(screenshot).toBeGolden('transparent.png');
    });
    it('should render white background on jpeg file', async () => {
      const {page, server} = getTestState();

      await page.setViewport({width: 100, height: 100});
      await page.goto(server.EMPTY_PAGE);
      const screenshot = await page.screenshot({
        omitBackground: true,
        type: 'jpeg',
      });
      expect(screenshot).toBeGolden('white.jpg');
    });
    it('should work with webp', async () => {
      const {page, server} = getTestState();

      await page.setViewport({width: 100, height: 100});
      await page.goto(server.PREFIX + '/grid.html');
      const screenshot = await page.screenshot({
        type: 'webp',
      });

      expect(screenshot).toBeInstanceOf(Buffer);
    });
    it('should work with odd clip size on Retina displays', async () => {
      const {page} = getTestState();

      const screenshot = await page.screenshot({
        clip: {
          x: 0,
          y: 0,
          width: 11,
          height: 11,
        },
      });
      expect(screenshot).toBeGolden('screenshot-clip-odd-size.png');
    });
    it('should return base64', async () => {
      const {page, server} = getTestState();

      await page.setViewport({width: 500, height: 500});
      await page.goto(server.PREFIX + '/grid.html');
      const screenshot = await page.screenshot({
        encoding: 'base64',
      });
      // TODO (@jackfranklin): improve the screenshot types.
      // - if we pass encoding: 'base64', it returns a string
      // - else it returns a buffer.
      // If we can fix that we can avoid this "as string" here.
      expect(Buffer.from(screenshot as string, 'base64')).toBeGolden(
        'screenshot-sanity.png'
      );
    });
    it('should work in "fromSurface: false" mode', async () => {
      const {page, server} = getTestState();

      await page.setViewport({width: 500, height: 500});
      await page.goto(server.PREFIX + '/grid.html');
      const screenshot = await page.screenshot({
        fromSurface: false,
      });
      expect(screenshot).toBeDefined(); // toBeGolden('screenshot-fromsurface-false.png');
    });
  });

  describe('ElementHandle.screenshot', function () {
    it('should work', async () => {
      const {page, server} = getTestState();

      await page.setViewport({width: 500, height: 500});
      await page.goto(server.PREFIX + '/grid.html');
      await page.evaluate(() => {
        return window.scrollBy(50, 100);
      });
      const elementHandle = (await page.$('.box:nth-of-type(3)'))!;
      const screenshot = await elementHandle.screenshot();
      expect(screenshot).toBeGolden('screenshot-element-bounding-box.png');
    });
    it('should work with a null viewport', async () => {
      const {defaultBrowserOptions, puppeteer, server} = getTestState();

      const browser = await puppeteer.launch({
        ...defaultBrowserOptions,
        defaultViewport: null,
      });

      try {
        const page = await browser.newPage();
        await page.goto(server.PREFIX + '/grid.html');
        await page.evaluate(() => {
          return window.scrollBy(50, 100);
        });
        const elementHandle = (await page.$('.box:nth-of-type(3)'))!;
        const screenshot = await elementHandle.screenshot();
        expect(screenshot).toBeTruthy();
      } finally {
        await browser.close();
      }
    });
    it('should take into account padding and border', async () => {
      const {page} = getTestState();

      await page.setViewport({width: 500, height: 500});
      await page.setContent(`
        something above
        <style>div {
          border: 2px solid blue;
          background: green;
          width: 50px;
          height: 50px;
        }
        </style>
        <div></div>
      `);
      const elementHandle = (await page.$('div'))!;
      const screenshot = await elementHandle.screenshot();
      expect(screenshot).toBeGolden('screenshot-element-padding-border.png');
    });
    it('should capture full element when larger than viewport', async () => {
      const {page} = getTestState();

      await page.setViewport({width: 500, height: 500});

      await page.setContent(`
          something above
          <style>
          div.to-screenshot {
            border: 1px solid blue;
            width: 600px;
            height: 600px;
            margin-left: 50px;
          }
          ::-webkit-scrollbar{
            display: none;
          }
          </style>
          <div class="to-screenshot"></div>
        `);
      const elementHandle = (await page.$('div.to-screenshot'))!;
      const screenshot = await elementHandle.screenshot();
      expect(screenshot).toBeGolden(
        'screenshot-element-larger-than-viewport.png'
      );

      expect(
        await page.evaluate(() => {
          return {
            w: window.innerWidth,
            h: window.innerHeight,
          };
        })
      ).toEqual({w: 500, h: 500});
    });
    it('should scroll element into view', async () => {
      const {page} = getTestState();

      await page.setViewport({width: 500, height: 500});
      await page.setContent(`
        something above
        <style>div.above {
          border: 2px solid blue;
          background: red;
          height: 1500px;
        }
        div.to-screenshot {
          border: 2px solid blue;
          background: green;
          width: 50px;
          height: 50px;
        }
        </style>
        <div class="above"></div>
        <div class="to-screenshot"></div>
      `);
      const elementHandle = (await page.$('div.to-screenshot'))!;
      const screenshot = await elementHandle.screenshot();
      expect(screenshot).toBeGolden(
        'screenshot-element-scrolled-into-view.png'
      );
    });
    it('should work with a rotated element', async () => {
      const {page} = getTestState();

      await page.setViewport({width: 500, height: 500});
      await page.setContent(`<div style="position:absolute;
                                        top: 100px;
                                        left: 100px;
                                        width: 100px;
                                        height: 100px;
                                        background: green;
                                        transform: rotateZ(200deg);">&nbsp;</div>`);
      const elementHandle = (await page.$('div'))!;
      const screenshot = await elementHandle.screenshot();
      expect(screenshot).toBeGolden('screenshot-element-rotate.png');
    });
    it('should fail to screenshot a detached element', async () => {
      const {page} = getTestState();

      await page.setContent('<h1>remove this</h1>');
      const elementHandle = (await page.$('h1'))!;
      await page.evaluate((element: HTMLElement) => {
        return element.remove();
      }, elementHandle);
      const screenshotError = await elementHandle.screenshot().catch(error => {
        return error;
      });
      expect(screenshotError.message).toBe(
        'Node is either not visible or not an HTMLElement'
      );
    });
    it('should not hang with zero width/height element', async () => {
      const {page} = getTestState();

      await page.setContent('<div style="width: 50px; height: 0"></div>');
      const div = (await page.$('div'))!;
      const error = await div.screenshot().catch(error_ => {
        return error_;
      });
      expect(error.message).toBe('Node has 0 height.');
    });
    it('should work for an element with fractional dimensions', async () => {
      const {page} = getTestState();

      await page.setContent(
        '<div style="width:48.51px;height:19.8px;border:1px solid black;"></div>'
      );
      const elementHandle = (await page.$('div'))!;
      const screenshot = await elementHandle.screenshot();
      expect(screenshot).toBeGolden('screenshot-element-fractional.png');
    });
    it('should work for an element with an offset', async () => {
      const {page} = getTestState();

      await page.setContent(
        '<div style="position:absolute; top: 10.3px; left: 20.4px;width:50.3px;height:20.2px;border:1px solid black;"></div>'
      );
      const elementHandle = (await page.$('div'))!;
      const screenshot = await elementHandle.screenshot();
      expect(screenshot).toBeGolden('screenshot-element-fractional-offset.png');
    });
  });
});