mocking with amd

gistfile1.js

// ----------------------------------------
// /path/to/dependency.js
define(function() {
  return {
    doSomethingWithIt: function() {
      // blah
    }
  };
});

// ----------------------------------------
// my_object.js
define(['/path/to/dependency'], function(myDependency) {  // <-- how do I mock this bugger in my test? :)

  function one() {
    myDependency.doSomethingWithIt();

    return 'blah';
  }
  function two() {

  }

  // api
  return {
    one: one,
    two: two
  };
});

// ----------------------------------------
// my_object_spec.js
// the object under test is my_object, so ideally
// I'd like to mock/stub myDependency
define(['my_object', '/path/to/dependency'], function(my_object, myDependency) {

  beforeEach(function() {
    sinon.stub(myDependency, 'doSomethingWithIt').returns('whatever');
  });

  afterEach(function() {
    myDependency.doSomethingWithIt.restore();
  });

  it('should call one() as we expect', function() {
    expect(my_object.one(), 'blah');
  });
});

You should be able to include the dependency in your test and stub methods on its external API and have those stubbed methods be used in your 'my_object' code.