BackstopJS Issue - Gulp File

var gulp         = require('gulp')
,   backstop     = require('backstopjs')
;

gulp.task('css-test', function() {
    // Relative paths required
    var config = require(__dirname  + '/tests/backstop/config.js')('tests/backstop');

    backstop('test', { config: config, });
});


gulp.task('css-reference', function() {
  // Absolute paths required
  var config = require(__dirname  + '/tests/backstop/config.js')(__dirname  + '/tests/backstop');

  backstop('reference', { config: config, });
});