To unload a module, it should be sufficient to do: delete require.cache[modulePath].

It is not very intuitive to have to do:

var moduleToUnload = require.cache[modulePath];
var parentChildren = moduleToUnload.parent.children;
var index = parentChildren.indexOf(moduleToUnload);
parentChildren.splice(index, 1);
delete require.cache[modulePath];

Moreover, even if node.js provides this feature, it is not very useful to have module.parent and module.children, so let's remove them to avoid any leak problem.