Export/require in test/full-app test doesn't work

I’m new to testing so maybe it’s obvious, but I have no clue why is this happening.

I have a file which looks like this:

class ExampleService {}
const exampleService = new ExampleService()
export {exampleService, ExampleService}

In another file, this works in the app but not in test/full-app test:

const { exampleService } = require('/example')

exampleService will be undefined during the test (but when I run the app normally, it works).

The funny thing is that this works in tests:

const { ExampleService } = require('/example')
const exampleService = new ExampleService()

What am I missing?