How can I send a test email of an actual post, and how can I send the entire post instead of a synop

I see that the Subscribe by Email is working, and I can send a test post. But the test post is a fixed post, and I'd really like to see what happens with an actual post - such as the latest post - which includes images. Is there a way to see this? The post in question is

Also, I understand it is possible to send the entire contents of the newsletter, and not just a synopsis. Where is that setting?