@johnf/react-native-owl/lib/commonjs/matchers.js

Visual regression testing for React Native

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.toMatchBaseline = void 0;
var _fs = _interopRequireDefault(require("fs"));
var _path = _interopRequireDefault(require("path"));
var _pixelmatch = _interopRequireDefault(require("pixelmatch"));
var _pngjs = require("pngjs");
function _interopRequireDefault(e) { return e && e.__esModule ? e : { default: e }; }
const toMatchBaseline = (latestPath, options = {
  threshold: 0.1,
  bottomCrop: 0
}) => {
  const platform = process.env.OWL_PLATFORM;
  const screenshotsDir = _path.default.join(_path.default.dirname(latestPath), '..', '..');
  const baselinePath = _path.default.join(screenshotsDir, 'baseline', platform, _path.default.basename(latestPath));
  if (latestPath === baselinePath) {
    return {
      message: () => 'Generated a fresh baseline, skipping comparison.',
      pass: true
    };
  }
  try {
    const diffPath = _path.default.join(screenshotsDir, 'diff', platform, _path.default.basename(latestPath));
    _fs.default.mkdirSync(_path.default.dirname(diffPath), {
      recursive: true
    });
    const baselineData = _fs.default.readFileSync(baselinePath);
    const baselineImage = _pngjs.PNG.sync.read(baselineData);
    const croppedHeight = baselineImage.height - (options.bottomCrop || 0);
    const croppedBaselineImage = new _pngjs.PNG({
      width: baselineImage.width,
      height: croppedHeight
    });
    _pngjs.PNG.bitblt(baselineImage, croppedBaselineImage, 0, 0, baselineImage.width, croppedHeight, 0, 0);
    const latestData = _fs.default.readFileSync(latestPath);
    const latestImage = _pngjs.PNG.sync.read(latestData);
    const croppedLatestImage = new _pngjs.PNG({
      width: baselineImage.width,
      height: croppedHeight
    });
    _pngjs.PNG.bitblt(latestImage, croppedLatestImage, 0, 0, baselineImage.width, croppedHeight, 0, 0);
    const diffImage = new _pngjs.PNG({
      width: baselineImage.width,
      height: croppedHeight
    });
    const diffPixelsCount = (0, _pixelmatch.default)(croppedBaselineImage.data, croppedLatestImage.data, diffImage.data, baselineImage.width, croppedHeight, {
      threshold: options?.threshold
    });
    if (diffPixelsCount === 0) {
      return {
        message: () => `Compared screenshot to match baseline. No differences were found.`,
        pass: true
      };
    }

    // Create and save the diff image
    _fs.default.writeFileSync(diffPath, _pngjs.PNG.sync.write(diffImage), {
      encoding: 'binary'
    });
    return {
      message: () => `Compared screenshot to match baseline. ${diffPixelsCount} were different.`,
      pass: diffPixelsCount === 0
    };
  } catch (error) {
    let message = 'Unknown error';
    if (error instanceof Error) {
      message = error.message;
    }
    return {
      message: () => `Screenshot diffing error - ${message}`,
      pass: false
    };
  }
};
exports.toMatchBaseline = toMatchBaseline;
expect.extend({
  toMatchBaseline
});
//# sourceMappingURL=matchers.js.map