For rules to trigger, the traffic must impact the sensor.
Without knowing the network topology this is hard to troubleshoot. If this test instance is a vm that's not processing the traffic for clients 'behind' it then how can it see traffic to trigger a rule?
What rule are you trying to trigger?
Example test; enable rule sid 498 on your NS instance and from the cli of that NS instance enter wget testmyids.com and see if that triggers an alert.