How to export function from module without nodeunit testing it?

I've got a few tests scattered throughout multiple files.

Currently I just run `nodeunit .`, nodeunit then tests them all successfully. Great!

But I want to export a function from one of my files so that another can call it. The problem is that when I run `nodeunit .` that function now gets called.

How can I run tests on all files? I'm used to python's `nose` library, which only tests functions that have `test` in the function name.

Do I need to move all tests into a seperate file to the functionality? I don't want to do that. I like putting tests adjacent to the code they're testing.

Start by reading nodeunit's test discovery and module-loading behavior around the `nodeunit .` command; the issue names no source files or tests. Compare how exported functions are treated with the desired adjacent-test layout. Done means all intended tests still run without invoking helper functions exported for reuse.

Written by the indexing model from the issue text.