Integration test rendering process - EmberJS

I'm writing an integration test for one of my addon components. I've also linked it to a sibling project using npm link:

.. projects/
.... my-project/
.... my-linked-project/

I use one of the my-linked-project mixins in the my-project component in question.

//my-project/addon/components/my-component/component.js
import Ember from 'ember';
import ExternalMixin from 'my-linked-project/mixins/foo'

export default Ember.Component.extend(ExternalMixin, {
    ...
}

This runs fine with the application running, but seems to hit some issues when I render it in my integration test.

//my-project/tests/integration/components/my-component-test.js
import { moduleForComponent, test } from 'ember-qunit';
import hbs from 'htmlbars-inline-precompile';

moduleForComponent('my-component', 'Integration description', {
    integration: true
}

test('should render', function() {
    this.render(hbs``);
}

However I get Error: Could not find module 'my-linked-project/mixins/foo'.

1. Where can I read more about what happens when render / hbs are called?
2. Could the issue be the location of the test file, which can't find the external linked project?