Using test support code from an ember addon

I have several ember apps which use a common shared ember-cli addon. This addon has common code like models, navigation etc. I also want this addon to provide common test support code like test helpers, factories to the ember apps. However if I remove tests from .npmignore in the addon, then the test resources gets built with the ember app.

Is there a way to use the addon in an ember app, but strip the addon's tests folder on build? Or perhaps there is a better way of achieving this?