text: const assert = require('assert');
  const browserslist = require('browserslist');
  const rules = require('../index.js');
  
  const MIN_RULES = 1;
  const MIN_BROWSERS = 1;
  const MIN_COVERAGE = 70;
  
  console.log('Base rules:\n',rules,'\n',);
  assert(rules.length >= MIN_RULES,
      `Min. allowed rules ${MIN_RULES}, but ${rules.length} loaded.`);
  
  const browsers = browserslist(rules);
  const coverage = browserslist.coverage( browsers );
  assert(browsers.length >= MIN_BROWSERS,
      `Min. supported browsers ${MIN_BROWSERS}, but ${browsers.length} covered.`);
  assert(coverage >= MIN_COVERAGE,
      `Coverage should be at least ${MIN_COVERAGE}%, but calculated coverage is ${coverage}%`);
  
  console.log('Browsers covered:\n', browsers.join('\n'));
  console.log('\n');
  console.log('Browser coverage: ', coverage);
  console.log('\n');
  