Embodiments of the present invention are directed to testing policy changes associated with a production network. A virtual network that represents at least a portion of the production network can be generated. A first transaction log based on a first execution of the virtual network using test traffic and a first set of policies that are implemented in the production network can be obtained. A second transaction log based on a second execution of the virtual network using the test traffic and a second set of policies to be implemented in the production network can be obtained. Based on a comparison of the first and second transaction logs, it can be determined whether the second set of policies has a desired effect in the virtual network.