CallTest.js

var Caller = artifacts.require("Caller.sol");
var Callee = artifacts.require("Callee.sol");
var abi = require("ethereumjs-abi");

contract("Caller and Callee", function(accounts) {
  it("invoke callee via caller", function() {
    var caller;
    var callee;
    return Caller.deployed().then(function(callerInstance) {
      caller = callerInstance;
      return Callee.deployed().then(function(calleeInstance) {
        callee = calleeInstance;
        var encoded = abi.methodID("addOne", []).toString("hex");
        return caller.invoke(callee.address, 0, "0x" + encoded);
      }).then(function() {
        return callee.counter.call();
      }).then(function(counter) {
        assert.equal(counter.toNumber(), 1, "count wasn't correctly");
      }).then(function() {
        var encoded = abi.methodID("addNum", [ "uint256" ]).toString("hex") + 
                      abi.rawEncode([ "uint256" ], [ 10 ]).toString("hex");
        return caller.invoke(callee.address, 0, "0x" + encoded);
      }).then(function() {
        return callee.counter.call();
      }).then(function(counter) {
        assert.equal(counter.toNumber(), 11, "count wasn't correctly");
      });
    });
  });
});