When testing new Campaigns in a live system it is likely that duplicate invite checking will be turned on for your system. This can make it difficult to send more than one test email in the duplicate hold out period.
One simple approach to overcome this issue is to use gmail.com addresses for testing.
Gmail address have the feature of being able to add "+" and a string to the email address and have the email delivered to the same gmail.com account. But the change will overcome the CustomerGauge duplicate checking system and be delivered as normal.
For example if you wanted to send 3 test invites you could use the following approach: