With Reply, you can not only send test emails but also choose which of your email accounts you want to test.
To send a test email:
Click on the sequence to open the Sequence details page.
Open the Steps tab.
Hover over a template on any step and click Edit.
In the Template edit window, expand the drop-down list next to the Save button, or select Send test email in the preview section and click on it.
5. The pop-up window opens: select the sender email account you want to check from the drop-down list, enter an email address to receive the test email or leave it pre-filled. Click Send.