status-mobile/visual-test/setup.js

const { configureToMatchImageSnapshot } = require('jest-image-snapshot');
const fs = require('fs');
const path = require('path');
const kebabCase = require('lodash/kebabCase');
const expect = require('expect');


const toMatchImage = configureToMatchImageSnapshot({
  comparisonMethod: 'ssim', failureThreshold: 0.002, failureThresholdType: 'percent'
});


expect.extend({ toMatchImage });

expect.extend({
  async toMatchImageSnapshot(screenName) {
    const platform = await device.getPlatform();
    const deviceName = await device.name.split(' ').slice(1).join('');
    const deviceType = 'iPhone 11 Pro';

    const SNAPSHOTS_DIR = `__image_snapshots__/${platform}/${deviceType}`;

    const { testPath, currentTestName } = this;

    const customSnapshotsDir = path.join(path.dirname(testPath), SNAPSHOTS_DIR);
    const customSnapshotIdentifier = kebabCase(`${path.basename(testPath)}-${currentTestName}-${screenName}`)

    const tempPath = await device.takeScreenshot(screenName);
    const image = fs.readFileSync(tempPath);
    expect(image).toMatchImage({ customSnapshotIdentifier, customSnapshotsDir });

    return { pass: true }
  },
});

global.jestExpect = expect


beforeAll(async () => {
  await device.launchApp();
});