buster.js testing cannot load my js-files

I've been banging my head at the wall since yesterday (only interrupted by a great Bruce Springsteen concert last night... ;-)

I am trying to add some JS testing to an existing (Rails) project. Basically the folder structure is this:

.
├── app
│   └── assets
│       └── javascripts
│           └── strftime.js
└── spec
    ├── buster.js
    └── javascripts
        └── strftime.test.js

In this very simple example I've taken the buster example from here https://gist.github.com/cjohansen/1904218 to be sure that everything worked before moving files around.

My buster.js looks like this:

var config = exports;

config["Server tests"] = {
    // sources: ["../app/assets/javascripts/strftime.js"],
    tests: ["javascripts/strftime.test.js"],

    env: "node"
};

and I've tried modifying the first 5 lines of strftime.test.js to this:

if (typeof require == "function" && typeof module == "object") {
    buster = require("buster");

    require("../app/assets/javascripts/strftime.js");
}

Currently when I run buster test, I get this:

$ buster test
Failed requiring ./spec/javascripts/strftime.test.js: Cannot find module '../app/assets/javascripts/lib/strftime.js'

If I try to uncomment the sources line, buster test fails silently - even if I try to run it with high debug level.

I've zipped the entire example (2 KB) and put it here, if anyone would like try give it a try: http://gehling.dk/b2.zip

UPDATE: I've managed to require the js-file successfully by supplying the path relative to my test-js file:

if (typeof require == "function" && typeof module == "object") {
    buster = require("buster");

    require("../../app/assets/javascripts/strftime.js");
}

But I still have the problem with buster failing silently, if I add the sources parameter.

TIA

/ Carsten