Expand these tests and add a few
Expand these tests and add a few

This is slightly easier to read since the code under test and assetions
are not spread apart as much.  It also adds some more tests for database
fixtures and mark as well as a (failing) test for the email API.

pombredanne/pytest_django,reincubate/pytest-django,thedrow/pytest-django,bforchhammer/pytest-django,pelme/pytest-django,aptivate/pytest-django,ojake/pytest-django,davidszotten/pytest-django,felixonmars/pytest-django,hoh/pytest-django,ktosiek/pytest-django,RonnyPfannschmidt/pytest_django,tomviner/pytest-django