This is looking pretty good :) Some stuff to fix, mostly stylistic.

Make sure all parameters align.

"succeeds".

This should be in sentence casing and end with a period.

"Send e-mails when new users register an account"

Can you change this to:

siteconfig = SiteConfiguration.objects.get_current()

This will guarantee it goes through our SiteConfiguration object cache/manager.

Can you change this to:

"New Review Board user registration for %s" % user.username

David may have better ideas for the subject.

Best to do:

context = {
   'domain': ...,
   'domain_method': ...,
   ...
}

I know the other unit tests aren't in this style, but please change this to "test_new_user_email". We're slowly migrating to this style for unit test functions.

Should end with a period.

Always a space after the :

Also, when you have a lot to list, do:

new_user_info = {
   'username': ...,
   ...
}

One last thing: best to use @example.com for test e-mail addresses.

First should be a get, I believe. Then do a post.

Can you group the two gets/posts together, and have the comment before it? (Plus a blank line before the comment.)

The "[Django] " shouldn't be hard-coded. Instead, replace "[Django ]" with settings.EMAIL_SUBJECT_PREFIX.

Actually, this should live in accounts/signals.py.

Thanks! Committed with a few small text tweaks.