index.js

const resemble = require("resemblejs");
const fs = require('fs');
const assert = require('assert');
const mkdirp = require('mkdirp');
const getDirName = require('path').dirname;
const AWS = require('aws-sdk');
const path = require('path');
const sizeOf = require('image-size');

/**
 * Resemble.js helper class for CodeceptJS, this allows screen comparison
 * @author Puneet Kala
 */

class ResembleHelper extends Helper {

  constructor(config) {
    super(config);
    this.baseFolder = this.resolvePath(config.baseFolder);
    this.diffFolder = this.resolvePath(config.diffFolder);
    this.screenshotFolder = global.output_dir + "/";
    this.prepareBaseImage = config.prepareBaseImage;
  }

  resolvePath(folderPath) {
    if (!path.isAbsolute(folderPath)) {
      return path.resolve(global.codecept_dir, folderPath) + "/";
    }
    return folderPath;
  }

  /**
   * Compare Images
   *
   * @param image
   * @param options
   * @returns {Promise<resolve | reject>}
   */
  async _compareImages(image, options) {
    const baseImage = this._getBaseImagePath(image, options);
    const actualImage = this._getActualImagePath(image);
    const diffImage = this._getDiffImagePath(image);

    // check whether the base and the screenshot images are present.
    fs.access(baseImage, fs.constants.F_OK | fs.constants.R_OK, (err) => {
      if (err) {
        throw new Error(
          `${baseImage} ${err.code === 'ENOENT' ? 'base image does not exist' :
            'base image has an access error'}`);
      }
    });

    fs.access(actualImage, fs.constants.F_OK | fs.constants.R_OK, (err) => {
      if (err) {
        throw new Error(
          `${actualImage} ${err.code === 'ENOENT' ? 'screenshot image does not exist' :
            'screenshot image has an access error'}`);
      }
    });

    return new Promise((resolve, reject) => {

      if (!options.outputSettings) {
        options.outputSettings = {};
      }
      resemble.outputSettings({
        boundingBox: options.boundingBox,
        ignoredBox: options.ignoredBox,
        ...options.outputSettings,
      });

      this.debug("Tolerance Level Provided " + options.tolerance);
      const tolerance = options.tolerance;

      resemble.compare(baseImage, actualImage, options, (err, data) => {
        if (err) {
          reject(err);
        } else {
          if (!data.isSameDimensions) {
            let dimensions1 = sizeOf(baseImage);
            let dimensions2 = sizeOf(actualImage);
            reject(new Error(`The base image is of ${dimensions1.height} X ${dimensions1.width} and actual image is of ${dimensions2.height} X ${dimensions2.width}. Please use images of same dimensions so as to avoid any unexpected results.`));
          }
          resolve(data);
          if (data.misMatchPercentage >= tolerance) {
            if (!fs.existsSync(getDirName(diffImage))) {
              fs.mkdirSync(getDirName(diffImage));
            }
            fs.writeFileSync(diffImage, data.getBuffer());
            const diffImagePath = path.join(process.cwd(), diffImage);
            this.debug(`Diff Image File Saved to: ${diffImagePath}`);
          }
        }
      });
    });
  }

  /**
   *
   * @param image
   * @param options
   * @returns {Promise<*>}
   */
  async _fetchMisMatchPercentage(image, options) {
    const result = this._compareImages(image, options);
    const data = await Promise.resolve(result);
    return data.misMatchPercentage;
  }

  /**
   * Take screenshot of individual element.
   * @param selector selector of the element to be screenshotted
   * @param name name of the image
   * @returns {Promise<void>}
   */
  async screenshotElement(selector, name) {
    const helper = this._getHelper();
    if (this.helpers['Puppeteer'] || this.helpers['Playwright']) {
      await helper.waitForVisible(selector);
      const els = await helper._locate(selector);
      if (!els.length) throw new Error(`Element ${selector} couldn't be located`);
      const el = els[0];

      await el.screenshot({path: `${global.output_dir}/${name}.png`});
    } else if (this.helpers['WebDriver']) {
      await helper.waitForVisible(selector);
      const els = await helper._locate(selector);
      if (!els.length) throw new Error(`Element ${selector} couldn't be located`);
      const el = els[0];

      await el.saveScreenshot(this.screenshotFolder + name + '.png');
    } else if (this.helpers['TestCafe']) {
      await helper.waitForVisible(selector);
      const els = await helper._locate(selector);
      if (!await els.count) throw new Error(`Element ${selector} couldn't be located`);
      const { t } = this.helpers['TestCafe'];

      await t.takeElementScreenshot(els, name);
    } else throw new Error("Method only works with Playwright, Puppeteer, WebDriver or TestCafe helpers.");
  }

  /**
   * This method attaches image attachments of the base, screenshot and diff to the allure reporter when the mismatch exceeds tolerance.
   * @param baseImage
   * @param misMatch
   * @param options
   * @returns {Promise<void>}
   */

  async _addAttachment(baseImage, misMatch, options) {
    const allure = codeceptjs.container.plugins('allure');

    if (allure !== undefined && misMatch >= options.tolerance) {
      allure.addAttachment('Base Image', fs.readFileSync(this._getBaseImagePath(baseImage, options)), 'image/png');
      allure.addAttachment('Screenshot Image', fs.readFileSync(this._getActualImagePath(baseImage)), 'image/png');
      allure.addAttachment('Diff Image', fs.readFileSync(this._getDiffImagePath(baseImage)), 'image/png');
    }
  }

  /**
   * This method attaches context, and images to Mochawesome reporter when the mismatch exceeds tolerance.
   * @param baseImage
   * @param misMatch
   * @param options
   * @returns {Promise<void>}
   */

  async _addMochaContext(baseImage, misMatch, options) {
    const mocha = this.helpers['Mochawesome'];

    if (mocha !== undefined && misMatch >= options.tolerance) {
      await mocha.addMochawesomeContext("Base Image");
      await mocha.addMochawesomeContext(this._getBaseImagePath(baseImage, options));
      await mocha.addMochawesomeContext("ScreenShot Image");
      await mocha.addMochawesomeContext(this._getActualImagePath(baseImage));
      await mocha.addMochawesomeContext("Diff Image");
      await mocha.addMochawesomeContext(this._getDiffImagePath(baseImage));
    }
  }

  /**
   * This method uploads the diff and screenshot images into the bucket with diff image under bucketName/diff/diffImage and the screenshot image as
   * bucketName/output/ssImage
   * @param accessKeyId
   * @param secretAccessKey
   * @param region
   * @param bucketName
   * @param baseImage
   * @param options
   * @returns {Promise<void>}
   */

  async _upload(accessKeyId, secretAccessKey, region, bucketName, baseImage, options) {
    console.log("Starting Upload... ");
    const s3 = new AWS.S3({
      accessKeyId: accessKeyId,
      secretAccessKey: secretAccessKey,
      region: region
    });
    fs.readFile(this._getActualImagePath(baseImage), (err, data) => {
      if (err) throw err;
      let base64data = new Buffer(data, 'binary');
      const params = {
        Bucket: bucketName,
        Key: `output/${baseImage}`,
        Body: base64data
      };
      s3.upload(params, (uErr, uData) => {
        if (uErr) throw uErr;
        console.log(`Screenshot Image uploaded successfully at ${uData.Location}`);
      });
    });
    fs.readFile(this._getDiffImagePath(baseImage), (err, data) => {
      if (err) console.log("Diff image not generated");
      else {
        let base64data = new Buffer(data, 'binary');
        const params = {
          Bucket: bucketName,
          Key: `diff/Diff_${baseImage}`,
          Body: base64data
        };
        s3.upload(params, (uErr, uData) => {
          if (uErr) throw uErr;
          console.log(`Diff Image uploaded successfully at ${uData.Location}`)
        });
      }
    });

    // If prepareBaseImage is false, then it won't upload the baseImage. However, this parameter is not considered if the config file has a prepareBaseImage set to true.
    if (this._getPrepareBaseImage(options)) {
      const baseImageName = this._getBaseImageName(baseImage, options);

      fs.readFile(this._getBaseImagePath(baseImage, options), (err, data) => {
        if (err) throw err;
        else {
          let base64data = new Buffer(data, 'binary');
          const params = {
            Bucket: bucketName,
            Key: `base/${baseImageName}`,
            Body: base64data
          };
          s3.upload(params, (uErr, uData) => {
            if (uErr) throw uErr;
            console.log(`Base Image uploaded at ${uData.Location}`)
          });
        }
      });
    } else {
      console.log("Not Uploading base Image");
    }
  }

  /**
   * This method downloads base images from specified bucket into the base folder as mentioned in config file.
   * @param accessKeyId
   * @param secretAccessKey
   * @param region
   * @param bucketName
   * @param baseImage
   * @param options
   * @returns {Promise<void>}
   */

  _download(accessKeyId, secretAccessKey, region, bucketName, baseImage, options) {
    console.log("Starting Download...");
    const baseImageName = this._getBaseImageName(baseImage, options);
    const s3 = new AWS.S3({
      accessKeyId: accessKeyId,
      secretAccessKey: secretAccessKey,
      region: region
    });
    const params = {
      Bucket: bucketName,
      Key: `base/${baseImageName}`
    };
    return new Promise((resolve) => {
      s3.getObject(params, (err, data) => {
        if (err) console.error(err);
        console.log(this._getBaseImagePath(baseImage, options));
        fs.writeFileSync(this._getBaseImagePath(baseImage, options), data.Body);
        resolve("File Downloaded Successfully");
      });
    });
  }

  /**
   * Check Visual Difference for Base and Screenshot Image
   * @param baseImage         Name of the Base Image (Base Image path is taken from Configuration)
   * @param options           Options ex {prepareBaseImage: true, tolerance: 5} along with Resemble JS Options, read more here: https://github.com/rsmbl/Resemble.js
   * @returns {Promise<void>}
   */
  async seeVisualDiff(baseImage, options) {
    await this._assertVisualDiff(undefined, baseImage, options);
  }

  /**
   * See Visual Diff for an Element on a Page
   *
   * @param selector   Selector which has to be compared expects these -> CSS|XPath|ID
   * @param baseImage  Base Image for comparison
   * @param options    Options ex {prepareBaseImage: true, tolerance: 5} along with Resemble JS Options, read more here: https://github.com/rsmbl/Resemble.js
   * @returns {Promise<void>}
   */
  async seeVisualDiffForElement(selector, baseImage, options) {
    await this._assertVisualDiff(selector, baseImage, options);
  }

  async _assertVisualDiff(selector, baseImage, options) {
    if (!options) {
      options = {};
      options.tolerance = 0;
    }

    const awsC = this.config.aws;

    if (this._getPrepareBaseImage(options)) {
      await this._prepareBaseImage(baseImage, options);
    } else if (awsC !== undefined) {
      await this._download(awsC.accessKeyId, awsC.secretAccessKey, awsC.region, awsC.bucketName, baseImage, options);
    }

    if (selector) {
      options.boundingBox = await this._getBoundingBox(selector);
    }
    const misMatch = await this._fetchMisMatchPercentage(baseImage, options);
    this._addAttachment(baseImage, misMatch, options);
    this._addMochaContext(baseImage, misMatch, options);
    if (awsC !== undefined) {
      await this._upload(awsC.accessKeyId, awsC.secretAccessKey, awsC.region, awsC.bucketName, baseImage, options)
    }

    this.debug("MisMatch Percentage Calculated is " + misMatch + " for baseline " + baseImage);

    if (!options.skipFailure) {
      assert(misMatch <= options.tolerance, "Screenshot does not match with the baseline " + baseImage + " when MissMatch Percentage is " + misMatch);
    }
  }

  /**
   * Function to prepare Base Images from Screenshots
   *
   * @param screenShotImage  Name of the screenshot Image (Screenshot Image Path is taken from Configuration)
   * @param options
   */
  async _prepareBaseImage(screenShotImage, options) {
  	const baseImage = this._getBaseImagePath(screenShotImage, options);
  	const actualImage = this._getActualImagePath(screenShotImage);

    await this._createDir(baseImage);

    fs.access(actualImage, fs.constants.F_OK | fs.constants.W_OK, (err) => {
      if (err) {
        throw new Error(
          `${actualImage} ${err.code === 'ENOENT' ? 'does not exist' : 'is read-only'}`);
      }
    });

    fs.access(this.baseFolder, fs.constants.F_OK | fs.constants.W_OK, (err) => {
      if (err) {
        throw new Error(
          `${this.baseFolder} ${err.code === 'ENOENT' ? 'does not exist' : 'is read-only'}`);
      }
    });

    fs.copyFileSync(actualImage, baseImage);
  }

  /**
   * Function to create Directory
   * @param directory
   * @returns {Promise<void>}
   * @private
   */
  _createDir(directory) {
    mkdirp.sync(getDirName(directory));
  }

  /**
   * Function to fetch Bounding box for an element, fetched using selector
   *
   * @param selector CSS|XPath|ID selector
   * @returns {Promise<{boundingBox: {left: *, top: *, right: *, bottom: *}}>}
   */
  async _getBoundingBox(selector) {
    const helper = this._getHelper();
    await helper.waitForVisible(selector);
    const els = await helper._locate(selector);

    if (this.helpers['TestCafe']) {
      if (await els.count != 1) throw new Error(`Element ${selector} couldn't be located or isn't unique on the page`);
    }
    else {
      if (!els.length) throw new Error(`Element ${selector} couldn't be located`);
    }

    let location, size;

    if (this.helpers['Puppeteer'] || this.helpers['Playwright']) {
      const el = els[0];
      const box = await el.boundingBox();
      size = location = box;
    }

    if (this.helpers['WebDriver'] || this.helpers['Appium']) {
      const el = els[0];
      location = await el.getLocation();
      size = await el.getSize();
    }

    if (this.helpers['WebDriverIO']) {
      location = await helper.browser.getLocation(selector);
      size = await helper.browser.getElementSize(selector);
    }
    if (this.helpers['TestCafe']) {
      return await els.boundingClientRect;
    }

    if (!size) {
      throw new Error("Cannot get element size!");
    }

    const bottom = size.height + location.y;
    const right = size.width + location.x;
    const boundingBox = {
      left: location.x,
      top: location.y,
      right: right,
      bottom: bottom
    };

    this.debugSection('Area', JSON.stringify(boundingBox));

    return boundingBox;
  }

  _getHelper() {
    if (this.helpers['Puppeteer']) {
      return this.helpers['Puppeteer'];
    }

    if (this.helpers['WebDriver']) {
      return this.helpers['WebDriver'];
    }
    if (this.helpers['Appium']) {
      return this.helpers['Appium'];
    }
    if (this.helpers['WebDriverIO']) {
      return this.helpers['WebDriverIO'];
    }
    if (this.helpers['TestCafe']) {
      return this.helpers['TestCafe'];
    }

    if (this.helpers['Playwright']) {
      return this.helpers['Playwright'];
    }

    throw new Error('No matching helper found. Supported helpers: Playwright/WebDriver/Appium/Puppeteer/TestCafe');
  }

  /**
   * Returns the final name of the expected base image, without a path
   * @param image Name of the base-image, without path
   * @param options Helper options
   * @returns {string}
   */
  _getBaseImageName(image, options) {
  	return (options.compareWithImage ? options.compareWithImage : image);
  }

  /**
   * Returns the path to the expected base image
   * @param image Name of the base-image, without path
   * @param options Helper options
   * @returns {string}
   */
  _getBaseImagePath(image, options) {
    return this.baseFolder + this._getBaseImageName(image, options);
  }

  /**
   * Returns the path to the actual screenshot image
   * @param image Name of the image, without path
   * @returns {string}
   */
  _getActualImagePath(image) {
  	return this.screenshotFolder + image;
  }

  /**
   * Returns the path to the image that displays differences between base and actual image.
   * @param image Name of the image, without path
   * @returns {string}
   */
  _getDiffImagePath(image) {
  	const diffImage = "Diff_" + image.split(".")[0] + ".png";
  	return this.diffFolder + diffImage;
  }

  /**
   * Returns the final `prepareBaseImage` flag after evaluating options and config values
   * @param options Helper options
   * @returns {boolean}
   */
  _getPrepareBaseImage(options) {
    if ('undefined' !== typeof options.prepareBaseImage) {
      // Cast to bool with `!!` for backwards compatibility
      return !! options.prepareBaseImage;
    } else {
      // Compare with `true` for backwards compatibility
      return true === this.prepareBaseImage;
    }
  }
}

module.exports = ResembleHelper;