Node CLI Unit Testing

I have a node module I am working on, and I want to write unit tests for it, however I am confused on how I would pass arguments (required for the CLI) to node through a testing suite.

Lets assume (for brevity) the module name is J, so I would call it like...

$ j --file test.js --file test2.js

how do i recreate those --file calls when I am writing my testing suite?