To be able to test this you need to add some providers to one of these encounters. E.g. in EncounterDataLibrary-testData.xml you'll need to add something along the lines of:
    < encounter_provider encounter_provider_id="1" encounter_id="3" provider_id="1" encounter_role_id="1" creator="1" date_created="2006-03-11 15:57:35.0" voided="false" uuid="19e0aae8-20ee-46b7-ade6-9e68f897b7a9" />
    < provider provider_id="1" person_id="1" identifier="Test" creator="1" date_created="2005-01-01 00:00:00.0" retired="false" uuid="c2299800-cca9-11e0-9572-0800200c9a66" />
    this provider should have a < person > and that person should have a < person_name >

EncounterRole values are already in coreMetadata.xml, e.g. 8 is "Assisting Surgeon".