fix: karma gulp script

Author: FabianAlbrecht

gulpfile.js

@@ -8,7 +8,9 @@ gulp.task('karma', function(done) {
  configFile: __dirname + '/karma.conf.js',
  singleRun: true,
  browsers: ['Firefox', 'Chrome']
- }, done);
+ }, function() {
+ done();
+ });
 });
 
 gulp.task('build-files', function() {