chai.use(chaiHttp); Once or in every test file?

Adding Chai HTTP (https://www.chaijs.com/plugins/chai-http/) to a Node project tests.

Using the plugin (as in the documentation) is using:

var chai = require('chai')
  , chaiHttp = require('chai-http');

chai.use(chaiHttp);

I’m wonder if I need to add chai.use(chaiHttp); in every test file I’m using chaiHttp? or can I setup chaiHttp once in one of the tests?

can it be in a common file?