gistfile1.js

// the test case
function testReaddir() {
   fs.readdir(basedir, function(e,r) {
        vassert.assertTrue(r.length>0);
        vassert.testComplete();
    })
}

//try 1
this.readdir = function(path, callback) {
    vertx.fileSystem.readDir(path, function(result) {
      callback();
    } );
  }

//try 2
this.readdir = function(path, callback) {
    vertx.fileSystem.readDir(path, function(err, res) {
      callback(err,res);
    } );
  }

//try 3
 this.readdir = function(path, callback) {
    vertx.fileSystem.readDir(path, function(err, res) {
      callback();
    } );
  }


// direct binding works
 this.readdir = vertx.fileSystem.readDir.bind( vertx.fileSystem );