test(e2e): store images in jpeg format

e2e/jest.config.js

@@ -10,7 +10,7 @@ module.exports = {
   roots: ['./tests/'],
   testRegex: ['(.+)\\.(spec|test)\\.ts$', '(.+).feature'],
   moduleFileExtensions: ['ts', 'js', 'feature'],
-  setupFilesAfterEnv: ['./setup/image.ts', './setup/scenarios.ts'],
+  setupFilesAfterEnv: ['./setup/serializers/image.ts', './setup/scenarios.ts'],
   reporters: [
     ['./reporters/reporter.js', {
       diffDir: './.diff',

e2e/package.json

@@ -15,11 +15,13 @@
   },
   "dependencies": {
     "@types/jest-environment-puppeteer": "^5.0.6",
-    "@types/jest-image-snapshot": "^6.4.0",
+    "@types/pixelmatch": "^5.2.6",
     "@types/puppeteer": "^7.0.4",
-    "jest-image-snapshot": "^6.4.0",
-    "jest-puppeteer": "^10.0.1",
-    "puppeteer": "^22.15.0",
+    "jest-puppeteer": "^10.1.0",
+    "looks-same": "^9.0.0",
+    "pixelmatch": "^5.3.0",
+    "puppeteer": "^23.1.0",
+    "sharp": "^0.33.4",
     "stucumber": "^0.19.0"
   }
 }

e2e/setup/scenarios.screenshot.ts

@@ -1,11 +1,6 @@
 import {cucumber} from '../transformer/gherkin';
 
 import type {TestEnv} from './scenarios.env';
-import type {MatchImageSnapshotOptions} from 'jest-image-snapshot';
-
-const DIFF_CONFIG: MatchImageSnapshotOptions = {
-  customDiffDir: '.diff'
-};
 
 cucumber.defineRule('take a screenshot', async ({screenshots}: TestEnv) => {
   screenshots.push(await page.screenshot());
@@ -29,14 +24,14 @@ cucumber.defineRule('take a screenshot of the element', async ({elements, screen
   screenshots.push(await element.screenshot());
 });
 
-cucumber.defineRule('check if the screenshot is exactly equal to the snapshotted version', ({screenshots}: TestEnv) => {
+cucumber.defineRule('check if the screenshot is exactly equal to the snapshotted version', async ({screenshots}: TestEnv) => {
   if (!screenshots.length) throw new Error('E2E: there is no any screenshot, make sure you have "Take a screenshot" before');
   const image = screenshots.pop();
-  expect(image).toMatchImageSnapshot(DIFF_CONFIG);
+  expect(image).toMatchImageSnapshot();
 });
 
-cucumber.defineRule('check if the screenshot is equal to the snapshotted version', ({screenshots}: TestEnv) => {
+cucumber.defineRule('check if the screenshot is equal to the snapshotted version', async ({screenshots}: TestEnv) => {
   if (!screenshots.length) throw new Error('E2E: there is no any screenshot, make sure you have "Take a screenshot" before');
   const image = screenshots.pop();
-  expect(image).toMatchImageSnapshot({failureThreshold: 1000, blur: .005, comparisonMethod: 'ssim', failureThresholdType: 'pixel', ...DIFF_CONFIG});
+  expect(image).toMatchImageSnapshot({threshold: 0.1});
 });

e2e/setup/serializers/image.ts

@@ -0,0 +1,6 @@
+import {SnapshotMatcher} from './image/snapshot-matcher';
+import type {SnapshotMatcherOptions} from './image/snapshot-matcher';
+
+expect.extend({async toMatchImageSnapshot(received: Buffer, options: SnapshotMatcherOptions = {}) {
+  return new SnapshotMatcher(this, received, options).match();
+}});

e2e/setup/serializers/image/diff-builder.ts

@@ -0,0 +1,43 @@
+import sharp from 'sharp';
+import type {SharpContext} from './snapshot-matcher';
+
+type DiffBuilderConfig = {
+  diffPath: string;
+  img1: SharpContext;
+  img2: SharpContext;
+  diffBuffer: Buffer;
+};
+
+export class DiffBuilder {
+
+  protected imgInfo: {width: number, height: number};
+
+  constructor(protected config: DiffBuilderConfig) {
+    this.imgInfo = this.config.img1.info;
+  }
+
+  public async build(): Promise<void> {
+    const {diffPath, img1, img2, diffBuffer} = this.config;
+    const {width, height} = this.imgInfo;
+    await sharp({
+      create: {
+        width: width * 3,
+        height,
+        channels: 4,
+        background: {r: 0, g: 0, b: 0, alpha: 0}
+      }
+    })
+      .composite([
+        {input: await this.toWebp(img1.data), left: 0, top: 0},
+        {input: await this.toWebp(diffBuffer), left: width, top: 0},
+        {input: await this.toWebp(img2.data), left: width * 2, top: 0}
+      ])
+      .webp()
+      .toFile(diffPath);
+  }
+
+  protected toWebp(buffer: Buffer): Promise<Buffer> {
+    const {height, width} = this.imgInfo;
+    return sharp(buffer, {raw: {width, height, channels: 4}}).webp().toBuffer();
+  }
+}

e2e/setup/serializers/image/snapshot-matcher.ts

@@ -0,0 +1,94 @@
+import path from 'path';
+import fs from 'fs';
+import sharp from 'sharp';
+import pixelmatch from 'pixelmatch';
+
+import {DiffBuilder} from './diff-builder';
+
+export type SnapshotMatcherOptions = pixelmatch.PixelmatchOptions;
+
+export type SharpContext = {data: Buffer, info: sharp.OutputInfo};
+
+export class SnapshotMatcher {
+  protected static readonly DIFF_DIR = path.join(process.cwd(), '.diff');
+  protected static readonly SNAPSHOT_DIR = path.join(process.cwd(), 'tests', '__image_snapshots__');
+
+  protected static readonly defaultOptions: SnapshotMatcherOptions = {
+    diffMask: false,
+    alpha: 0,
+    diffColorAlt: [255, 255, 0],
+    includeAA: true,
+    threshold: 0.01
+  };
+
+  protected config: SnapshotMatcherOptions;
+  protected testName: string;
+  protected currentImg: sharp.Sharp;
+  protected shouldUpdateImg: boolean;
+
+  constructor(context: jest.MatcherContext, received: Buffer, options: SnapshotMatcherOptions = {}) {
+    this.testName = context.currentTestName!.replace(/([^a-z0-9]+)/gi, '-').toLowerCase();
+    this.config = Object.assign({}, SnapshotMatcher.defaultOptions, options);
+    this.currentImg = sharp(received).webp();
+    this.shouldUpdateImg = context.snapshotState._updateSnapshot === 'all';
+  }
+
+  public async match(): Promise<jest.CustomMatcherResult> {
+    this.updateDirectory(SnapshotMatcher.SNAPSHOT_DIR);
+    const prevImgPath = path.join(SnapshotMatcher.SNAPSHOT_DIR, `${this.testName}.webp`);
+    if (!fs.existsSync(prevImgPath) || this.shouldUpdateImg) {
+      await this.currentImg.toFile(prevImgPath);
+      return this.getMatcherResult(true, `New snapshot was created: ${prevImgPath}`);
+    }
+
+    const prevImg = await this.convertToRaw(prevImgPath);
+    const currImg = await this.convertToRaw(await this.currentImg.toBuffer());
+
+    let diffPath;
+    try {
+      diffPath = await this.compareImages(prevImg, currImg);
+    } catch (error) {
+      return this.getMatcherResult(false, `Error comparing snapshot to image ${prevImgPath}`);
+    }
+
+    if (diffPath) return this.getMatcherResult(false, `Image mismatch found: ${diffPath}`);
+    return this.getMatcherResult(true, `Image is the same as the snapshot: ${prevImgPath}`);
+  }
+
+  protected updateDirectory(dirPath: string): void {
+    if (!fs.existsSync(dirPath)) fs.mkdirSync(dirPath, {recursive: true});
+  }
+
+  protected getMatcherResult(pass: boolean, message: string): jest.CustomMatcherResult {
+    return {pass, message: () => message};
+  }
+
+  protected async convertToRaw(input: string | Buffer): Promise<SharpContext> {
+    return sharp(input).ensureAlpha().raw().toBuffer({resolveWithObject: true});
+  }
+
+  protected async compareImages(prevImg: SharpContext, currImg: SharpContext): Promise<string | undefined> {
+    let diffPath: string | undefined;
+    const {width, height} = prevImg.info;
+    const diffBuffer = Buffer.alloc(width * height * 4);
+    const numDiffPixel = pixelmatch(prevImg.data, currImg.data, diffBuffer, width, height, this.config);
+    if (numDiffPixel > width * height * 0.0001) diffPath = await this.saveDiff(prevImg, currImg, diffBuffer);
+    return diffPath;
+  }
+
+  protected async saveDiff(img1: SharpContext, img2: SharpContext, diffBuffer: Buffer): Promise<string> {
+    this.updateDirectory(SnapshotMatcher.DIFF_DIR);
+    const diffPath = path.join(SnapshotMatcher.DIFF_DIR, `${this.testName}-diff.webp`);
+    await new DiffBuilder({diffPath, img1, img2, diffBuffer}).build();
+    return diffPath;
+  }
+}
+
+declare global {
+  // eslint-disable-next-line @typescript-eslint/no-namespace
+  namespace jest {
+    export interface Matchers<R> {
+      toMatchImageSnapshot(options?: SnapshotMatcherOptions): Promise<R>;
+    }
+  }
+}