1 files changed, 147 insertions, 0 deletions
diff --git a/test/integration/visual.js b/test/integration/visual.js
new file mode 100644
index 0000000..f4410f9
--- /dev/null
+++ b/test/integration/visual.js
@@ -0,0 +1,147 @@
+/**
+@license
+Copyright (c) 2018 The Polymer Project Authors. All rights reserved.
+This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
+The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
+The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
+Code distributed by Google as part of the polymer project is also
+subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
+*/
+
+const puppeteer = require('puppeteer');
+const expect = require('chai').expect;
+const {startServer} = require('polyserve');
+const path = require('path');
+const fs = require('fs');
+const PNG = require('pngjs').PNG;
+const pixelmatch = require('pixelmatch');
+
+const currentDir = `${process.cwd()}/test/integration/screenshots-current`;
+const baselineDir = `${process.cwd()}/test/integration/screenshots-baseline`;
+
+describe('👀 page screenshots are correct', function() {
+  let polyserve, browser, page;
+
+  before(async function() {
+    polyserve = await startServer({port:4444, root:path.join(__dirname, '../..'), moduleResolution:'node'});
+
+    // Create the test directory if needed.
+    if (!fs.existsSync(currentDir)){
+      fs.mkdirSync(currentDir);
+    }
+    // And it's subdirectories.
+    if (!fs.existsSync(`${currentDir}/wide`)){
+      fs.mkdirSync(`${currentDir}/wide`);
+    }
+    if (!fs.existsSync(`${currentDir}/narrow`)){
+      fs.mkdirSync(`${currentDir}/narrow`);
+    }
+  });
+
+  after((done) => polyserve.close(done));
+
+  beforeEach(async function() {
+    browser = await puppeteer.launch();
+    page = await browser.newPage();
+  });
+
+  afterEach(() => browser.close());
+
+  describe('wide screen', function() {
+    beforeEach(async function() {
+      return page.setViewport({width: 800, height: 600});
+    });
+
+    it('/index.html', async function() {
+      return takeAndCompareScreenshot(page, '', 'wide');
+    });
+    it('/view1', async function() {
+      return takeAndCompareScreenshot(page, 'view1', 'wide');
+    });
+    it('/view2', async function() {
+      return takeAndCompareScreenshot(page, 'view2', 'wide');
+    });
+    it('/view3', async function() {
+      return takeAndCompareScreenshot(page, 'view3', 'wide');
+    });
+    it('/404', async function() {
+      return takeAndCompareScreenshot(page, 'batmanNotAView', 'wide');
+    });
+  });
+
+  describe('narrow screen', function() {
+    beforeEach(async function() {
+      return page.setViewport({width: 375, height: 667});
+    });
+
+    it('/index.html', async function() {
+      return takeAndCompareScreenshot(page, '', 'narrow');
+    });
+    it('/view1', async function() {
+      return takeAndCompareScreenshot(page, 'view1', 'narrow');
+    });
+    it('/view2', async function() {
+      return takeAndCompareScreenshot(page, 'view2', 'narrow');
+    });
+    it('/view3', async function() {
+      return takeAndCompareScreenshot(page, 'view3', 'narrow');
+    });
+    it('/404', async function() {
+      return takeAndCompareScreenshot(page, 'batmanNotAView', 'narrow');
+    });
+  });
+});
+
+async function takeAndCompareScreenshot(page, route, filePrefix) {
+  // If you didn't specify a file, use the name of the route.
+  let fileName = filePrefix + '/' + (route ? route : 'index');
+
+  await page.goto(`http://127.0.0.1:4444/${route}`);
+  await page.screenshot({path: `${currentDir}/${fileName}.png`});
+  return compareScreenshots(fileName);
+}
+
+function compareScreenshots(view) {
+  return new Promise((resolve, reject) => {
+    // Note: for debugging, you can dump the screenshotted img as base64.
+    // fs.createReadStream(`${currentDir}/${view}.png`, { encoding: 'base64' })
+    //   .on('data', function (data) {
+    //     console.log('got data', data)
+    //   })
+    //   .on('end', function () {
+    //     console.log('\n\n')
+    //   });
+    const img1 = fs.createReadStream(`${currentDir}/${view}.png`).pipe(new PNG()).on('parsed', doneReading);
+    const img2 = fs.createReadStream(`${baselineDir}/${view}.png`).pipe(new PNG()).on('parsed', doneReading);
+
+    let filesRead = 0;
+    function doneReading() {
+      // Wait until both files are read.
+      if (++filesRead < 2) return;
+
+      // The files should be the same size.
+      expect(img1.width, 'image widths are the same').equal(img2.width);
+      expect(img1.height, 'image heights are the same').equal(img2.height);
+
+      // Do the visual diff.
+      const diff = new PNG({width: img1.width, height: img1.height});
+
+      // Skip the bottom/rightmost row of pixels, since it seems to be
+      // noise on some machines :/
+      const width = img1.width - 1;
+      const height = img1.height - 1;
+
+      const numDiffPixels = pixelmatch(img1.data, img2.data, diff.data,
+          width, height, {threshold: 0.2});
+      const percentDiff = numDiffPixels/(width * height)*100;
+
+      const stats = fs.statSync(`${currentDir}/${view}.png`);
+      const fileSizeInBytes = stats.size;
+      console.log(`📸 ${view}.png => ${fileSizeInBytes} bytes, ${percentDiff}% different`);
+
+      //diff.pack().pipe(fs.createWriteStream(`${currentDir}/${view}-diff.png`));
+      expect(numDiffPixels, 'number of different pixels').equal(0);
+      resolve();
+    }
+  });
+}