diff-test.js

const fs = require('fs');
const path = require('path');

const imageDiff = require('image-diff');

const testCases = fs.readdirSync(path.join('/', 'visual-diff', 'results'));
const expectations = fs.readdirSync(path.join(__dirname, 'expectations'));

const localBasePath = path.join('test', 'visual-diff');
const dockerBasePath = path.join('/', 'visual-diff');

const expectedExtension = '.png';

describe('expecation has result', function() {

  expectations.forEach(function(expectation) {
    if (expectation.endsWith(expectedExtension)) {
      it(expectation, function() {
        if (testCases.indexOf(expectation) === -1) {
          expect('No result exists for expectation ' + expectation).toBeNull();
        }
      });
    }
  });

});

describe('result matches expectation', function() {

  testCases.forEach(function(testCase) {
    if (testCase.endsWith(expectedExtension)) {
      const testPath = path.join(dockerBasePath, 'results', testCase);
      const expectationPath = path.join(localBasePath, 'expectations', testCase);
      const diffPath = path.join(dockerBasePath, 'diff', testCase);

      it(testCase, function(done) {
        fs.access(path.join(__dirname, 'expectations', testCase), fs.R_OK, function(err) {
          if (err) {
            expect('No expectation exists for ' + testCase).toBeNull();
            done();
            return;
          }

          imageDiff.getFullResult({
            actualImage: testPath,
            expectedImage: expectationPath,
            diffImage: diffPath,
            shadow: true
          }, function(err, result) {
            expect(err).toBeNull();
            expect(result.percentage).toBeLessThan(0.01);
            done();
          });
        });

      });
    }
  });

});