When testing online reviews, if you re-email yourself the same work order or invoice it will default back to what you originally selected (which is what it is supposed to do). Once you select a star rating on one work order or invoice email, it will never overwrite that original rating. 

This is not a good test of Online Reviews.

To test Online Reviews, create a new Work Order and mark it complete for each test. 

For more information about getting started with Online Reviews, see: Online Reviews - getting started.