The return for POSTed data is exactly what is being checked in **every** test you write involving the POST call.  

For example, if you're checking what happens if the email isn't present in a post call, you have to figure out if the server's behaviour was expected or not.  The only way to check that is by looking at the return value - but this is part of the `it('should error if email is not present')` test!  In that test, you run the call without passing an email, and check the return code (probably `404`) and the return values on the data using `assert()`.  

Ask me for more info if this keeps confusing you - you're very close to understanding unit tests at a high level, and this is your last nit to figure out.