Sanity journeys can be created with the read audience + end activity and once this is published, you will have the profiles that entered the journey (as a result of being qualified into the audience) in step events dataset.
These profiles can then be verified (either by profile lookup or by writing queries on the respective datasets) if they indeed have the audience criteria.
You can load test data into the respective datasets having all the attributes that should satisfy the audience criteria and should see it being qualified into the audience based on the type of audience defined. If the same audience is being used in journey, those respective entrances can be seen in step events dataset.