Testing your campaign's deliverability
The best way to test if a campaign is hitting the inbox is to send a Regular campaign to a few email addresses you own. Not by sending a test email. The test email is meant for viewing the template to ensure the design is how you want it to look, and to check that your links are working. It is not a test for deliverability (hitting the inbox).
After sending a trial run of your campaign, you can send the same campaign again with the Duplicate feature. You can then delete the trial campaign.
Gmail Warning with a [Test] email
When sending a test email to yourself you may receive this warning in Gmail if you're Sending from email address is the same @gmail.com address you choose to send your test email to:
This message is often seen when sending a test email to yourself in Gmail.
We recommend you do NOT send your campaigns from an @gmail.com or other generic address but from an email address associated with your domain (email@example.com.) This helps email clients (like Gmail) authenticate who you are and can improve the deliverability of your campaigns to your subscribers.