Creating Tests for a play module

We're splitting up a larger play project into modules. One of these was a number of classes in a folder in app/util/webservices.

How can I run tests from within the module? There aren't any controllers, but why are those necessary? Running play test gives me:

conf/routes or conf/application.conf missing. module does not seem to host a valid application.

I saw this question: Testing Play Modules

But I was wondering if the test application would go within the module folder, or beside it in its own directory.