text: const postcss = require('postcss');
  const fs = require('fs');
  
  console.log('Testing files with abs');
  fs.readFile('test/test.css', (err, data) => {
      if (err) {
          console.log(err.message);
          process.exit(1);
      }
  
      postcss([
          require('../index.js')({
              abs: 'test'
          })
      ]).process(data.toString()).then((result) => {
          fs.readFile('test/expected-abs.css', (err, expected) => {
              if (err) {
                  console.log(err.message);
                  process.exit(1);
              }
  
              if (expected.toString().trim() !== result.css.trim()) {
                  console.log('Problems with css transformation.');
                  console.log('Expected result:');
                  console.log(expected.toString());
                  console.log('Actual result:');
                  console.log(result.css);
                  process.exit(2);
              } else {
                  console.log('Everything fine.');
                  process.exit(0);
              }
          });
      }).catch((e) => {
          console.log('Problem when rendering the css');
          process.exit(1);
      });
  });