The Arquillian Service deployed during execution has a Deployment Processor hook to scan for "Test Deployments" so it can lookup the Module etc during execution. This scan assumes the TestDeployment will contain JUnits @RunWith annotation, which is true for JUnit, but not so much for other test frameworks.

Arquillian is built to work with any test framework so TestNG/ScalaTest/Spock etc are all valid targets.

Since the Arquillian Service is no longer a pre installed service, but deployed only during test execution, it could make sense to remove the scanning(used to filter out test deployment) and just consume all deployments during it's life time.