Facebook: Have a friend or colleague who is not an admin of the Facebook page comment #donate on any post. They can also simply create a visitor post with #donate.
Twitter: You can test Twitter with your personal Twitter account. Tweet #donate + any amount at your nonprofit's handle (Ex: #donate $5 @nonprofit).
Donate Button: Have a friend or colleague try to donate via the button. They can donate by signing up with Facebook, Twitter or email.