playwright/test/page-screenshot.spec.ts

/**
 * Copyright 2018 Google Inc. All rights reserved.
 * Modifications copyright (c) Microsoft Corporation.
 *
 * 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 { it, expect, describe, options, verifyViewport } from './playwright.fixtures';
import path from 'path';
import fs from 'fs';

// Firefox headful produces a different image.

describe('page screenshot', (suite, parameters) => {
  suite.skip(options.FIREFOX(parameters) && !options.HEADLESS);
}, () => {
  it('should work', async ({page, server, golden}) => {
    await page.setViewportSize({width: 500, height: 500});
    await page.goto(server.PREFIX + '/grid.html');
    const screenshot = await page.screenshot();
    expect(screenshot).toMatchImage(golden('screenshot-sanity.png'));
  });

  it('should clip rect', async ({page, server, golden}) => {
    await page.setViewportSize({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).toMatchImage(golden('screenshot-clip-rect.png'));
  });

  it('should clip rect with fullPage', async ({page, server, golden}) => {
    await page.setViewportSize({width: 500, height: 500});
    await page.goto(server.PREFIX + '/grid.html');
    await page.evaluate(() => window.scrollBy(150, 200));
    const screenshot = await page.screenshot({
      fullPage: true,
      clip: {
        x: 50,
        y: 100,
        width: 150,
        height: 100,
      },
    });
    expect(screenshot).toMatchImage(golden('screenshot-clip-rect.png'));
  });

  it('should clip elements to the viewport', async ({page, server, golden}) => {
    await page.setViewportSize({width: 500, height: 500});
    await page.goto(server.PREFIX + '/grid.html');
    const screenshot = await page.screenshot({
      clip: {
        x: 50,
        y: 450,
        width: 1000,
        height: 100
      }
    });
    expect(screenshot).toMatchImage(golden('screenshot-offscreen-clip.png'));
  });

  it('should throw on clip outside the viewport', async ({page, server, golden}) => {
    await page.setViewportSize({width: 500, height: 500});
    await page.goto(server.PREFIX + '/grid.html');
    const screenshotError = await page.screenshot({
      clip: {
        x: 50,
        y: 650,
        width: 100,
        height: 100
      }
    }).catch(error => error);
    expect(screenshotError.message).toContain('Clipped area is either empty or outside the resulting image');
  });

  it('should run in parallel', async ({page, server, golden}) => {
    await page.setViewportSize({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]).toMatchImage(golden('grid-cell-1.png'));
  });

  it('should take fullPage screenshots', async ({page, server, golden}) => {
    await page.setViewportSize({width: 500, height: 500});
    await page.goto(server.PREFIX + '/grid.html');
    const screenshot = await page.screenshot({
      fullPage: true
    });
    expect(screenshot).toMatchImage(golden('screenshot-grid-fullpage.png'));
  });

  it('should restore viewport after fullPage screenshot', async ({page, server}) => {
    await page.setViewportSize({width: 500, height: 500});
    await page.goto(server.PREFIX + '/grid.html');
    const screenshot = await page.screenshot({ fullPage: true });
    expect(screenshot).toBeInstanceOf(Buffer);
    await verifyViewport(page, 500, 500);
  });

  it('should run in parallel in multiple pages', async ({server, context, golden}) => {
    const N = 5;
    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 % 2), y: 0, width: 50, height: 50 } }));
    const screenshots = await Promise.all(promises);
    for (let i = 0; i < N; ++i)
      expect(screenshots[i]).toMatchImage(golden(`grid-cell-${i % 2}.png`));
    await Promise.all(pages.map(page => page.close()));
  });

  it('should allow transparency', (test, parameters) => {
    test.fail(options.FIREFOX(parameters));
  }, async ({page, golden}) => {
    await page.setViewportSize({ width: 50, height: 150 });
    await page.setContent(`
      <style>
        body { margin: 0 }
        div { width: 50px; height: 50px; }
      </style>
      <div style="background:black"></div>
      <div style="background:white"></div>
      <div style="background:transparent"></div>
    `);
    const screenshot = await page.screenshot({omitBackground: true});
    expect(screenshot).toMatchImage(golden('transparent.png'));
  });

  it('should render white background on jpeg file', async ({page, server, golden}) => {
    await page.setViewportSize({ width: 100, height: 100 });
    await page.goto(server.EMPTY_PAGE);
    const screenshot = await page.screenshot({omitBackground: true, type: 'jpeg'});
    expect(screenshot).toMatchImage(golden('white.jpg'));
  });

  it('should work with odd clip size on Retina displays', async ({page, golden}) => {
    const screenshot = await page.screenshot({
      clip: {
        x: 0,
        y: 0,
        width: 11,
        height: 11,
      }
    });
    expect(screenshot).toMatchImage(golden('screenshot-clip-odd-size.png'));
  });

  it('should work with a mobile viewport', (test, parameters) => {
    test.skip(options.FIREFOX(parameters));
  }, async ({browser, server, golden}) => {
    const context = await browser.newContext({ viewport: { width: 320, height: 480 }, isMobile: true });
    const page = await context.newPage();
    await page.goto(server.PREFIX + '/overflow.html');
    const screenshot = await page.screenshot();
    expect(screenshot).toMatchImage(golden('screenshot-mobile.png'));
    await context.close();
  });

  it('should work with a mobile viewport and clip', (test, parameters) => {
    test.skip(options.FIREFOX(parameters));
  }, async ({browser, server, golden}) => {
    const context = await browser.newContext({viewport: { width: 320, height: 480 }, isMobile: true});
    const page = await context.newPage();
    await page.goto(server.PREFIX + '/overflow.html');
    const screenshot = await page.screenshot({ clip: { x: 10, y: 10, width: 100, height: 150 } });
    expect(screenshot).toMatchImage(golden('screenshot-mobile-clip.png'));
    await context.close();
  });

  it('should work with a mobile viewport and fullPage', (test, parameters) => {
    test.skip(options.FIREFOX(parameters));
  }, async ({browser, server, golden}) => {
    const context = await browser.newContext({viewport: { width: 320, height: 480 }, isMobile: true});
    const page = await context.newPage();
    await page.goto(server.PREFIX + '/overflow-large.html');
    const screenshot = await page.screenshot({ fullPage: true });
    expect(screenshot).toMatchImage(golden('screenshot-mobile-fullpage.png'));
    await context.close();
  });

  it('should work for canvas', async ({page, server, golden}) => {
    await page.setViewportSize({width: 500, height: 500});
    await page.goto(server.PREFIX + '/screenshots/canvas.html');
    const screenshot = await page.screenshot();
    expect(screenshot).toMatchImage(golden('screenshot-canvas.png'), { threshold: 0.3 });
  });

  it('should work for webgl', (test, parameters) => {
    test.fixme(options.FIREFOX(parameters));
    test.fixme(options.WEBKIT(parameters) && options.LINUX(parameters));
  }, async ({page, server, golden}) => {
    await page.setViewportSize({width: 640, height: 480});
    await page.goto(server.PREFIX + '/screenshots/webgl.html');
    const screenshot = await page.screenshot();
    expect(screenshot).toMatchImage(golden('screenshot-webgl.png'));
  });

  it('should work for translateZ', async ({page, server, golden}) => {
    await page.setViewportSize({width: 500, height: 500});
    await page.goto(server.PREFIX + '/screenshots/translateZ.html');
    const screenshot = await page.screenshot();
    expect(screenshot).toMatchImage(golden('screenshot-translateZ.png'));
  });

  it('should work while navigating', async ({page, server}) => {
    await page.setViewportSize({width: 500, height: 500});
    await page.goto(server.PREFIX + '/redirectloop1.html');
    for (let i = 0; i < 10; i++) {
      const screenshot = await page.screenshot({ fullPage: true }).catch(e => {
        if (e.message.includes('Cannot take a screenshot while page is navigating'))
          return Buffer.from('');
        throw e;
      });
      expect(screenshot).toBeInstanceOf(Buffer);
    }
  });

  it('should work with device scale factor', async ({browser, server, golden}) => {
    const context = await browser.newContext({ viewport: { width: 320, height: 480 }, deviceScaleFactor: 2 });
    const page = await context.newPage();
    await page.goto(server.PREFIX + '/grid.html');
    const screenshot = await page.screenshot();
    expect(screenshot).toMatchImage(golden('screenshot-device-scale-factor.png'));
    await context.close();
  });

  it('should work with iframe in shadow', async ({page, server, golden}) => {
    await page.setViewportSize({width: 500, height: 500});
    await page.goto(server.PREFIX + '/grid-iframe-in-shadow.html');
    expect(await page.screenshot()).toMatchImage(golden('screenshot-iframe.png'));
  });

  it('path option should work', async ({page, server, golden, testOutputDir}) => {
    await page.setViewportSize({width: 500, height: 500});
    await page.goto(server.PREFIX + '/grid.html');
    const outputPath = path.join(testOutputDir, 'screenshot.png');
    await page.screenshot({path: outputPath});
    expect(await fs.promises.readFile(outputPath)).toMatchImage(golden('screenshot-sanity.png'));
  });

  it('path option should create subdirectories', async ({page, server, golden, testOutputDir}) => {
    await page.setViewportSize({width: 500, height: 500});
    await page.goto(server.PREFIX + '/grid.html');
    const outputPath = path.join(testOutputDir, 'these', 'are', 'directories', 'screenshot.png');
    await page.screenshot({path: outputPath});
    expect(await fs.promises.readFile(outputPath)).toMatchImage(golden('screenshot-sanity.png'));
  });

  it('path option should detect jpeg', async ({page, server, golden, testOutputDir}) => {
    await page.setViewportSize({ width: 100, height: 100 });
    await page.goto(server.EMPTY_PAGE);
    const outputPath = path.join(testOutputDir, 'screenshot.jpg');
    const screenshot = await page.screenshot({omitBackground: true, path: outputPath});
    expect(await fs.promises.readFile(outputPath)).toMatchImage(golden('white.jpg'));
    expect(screenshot).toMatchImage(golden('white.jpg'));
  });

  it('path option should throw for unsupported mime type', async ({page}) => {
    const error = await page.screenshot({ path: 'file.txt' }).catch(e => e);
    expect(error.message).toContain('path: unsupported mime type "text/plain"');
  });
});