findResource seems to have trouble resolving URIs that contain query parameters. For example, this seems to work fine:
$locator = new UniformResourceLocator(MY_BASE_DIR);
$locator->addPath('assets', '', 'assets');
echo $locator->findResource('images/favicon.ico', false);
// prints "assets/images/favicon.ico"
However if I do this:
$locator = new UniformResourceLocator(MY_BASE_DIR);
$locator->addPath('assets', '', 'assets');
echo $locator->findResource('images/favicon.ico?v=2', false);
// prints the empty string
Not sure if this is the intended behavior.