Once you have verified the test, click the cleanup button.
The cleanup process will power-off the VMs and un-register them. The datastores will be unmounted and detached from the hosts. The SRA will then disconnect the volume from all hosts, destroy it and then eradicate it.
This resets the process to the original state. The only object that will remain through a cleanup is any point-in-time protection group snapshots that were created by the test. Those will be destroyed according to retention.