app-module-path/test/src/module-a/lib/index.js

Simple module to add additional directories to the Node module search for top-level app modules

var moduleB = require('module-b');
var installedModule = require('installed-module');

exports.sayHello = function() {
    console.log('Hello from module-a');
    moduleB.sayHello();
    installedModule.sayHello();
};