Use the newly working (thanks to Phil) Organization.is_owner(user)
method instead of long chain from org to user.
Minor comment changes.
Added docstring to test method.
Augmented TestCustomOrganizationAddForm.test_slug_generated_from_name so
that it tests that the slug that's auto-generated is unique.
Minor tidying to TestCustomOrganizationUserForm.
Some more tidying in forms_test, plus:
- use assertIn instead of assertTrue for testing if 'a in b' - get
  more descriptive message upon failure
- check that CustomOrganizationUserAddForm's is_editor value defaults as
  expected.
PEP-8 tidying.
Tidying of views_test plus:
- use assertIs instead of assertEqual for confirming identity of views
  class
- added TestCustomOrganizationUpdate to test new view
CustomOrganizationUpdate.
Removed code repetition by refactoring so that CustomOrganizationAddForm
is now a subclass of CustomOrganizationForm, the latter of which was added since Sarah
started her test refactoring branch, so have also added a test class for
it to forms_test.py.
Extracted code for editing Decision via admin screens from fixture based
TestCase subclass in open_consent_test_case.py into a new parent
TestCase subclass for the econsensus test suite, defined in new file
econsensus_testcase.py, so that tests that don't need fixtures can
access it.
Also renamed open_consent_test_case.py's class from
EconsensusTestCase to EconsensusFixtureTestCase, so that there's no
clash/confusion with the new EconsensusTestCase in
econsensus_testcase.py.
Altered test_status_set_in_get_and_get_context_data so that it not only
checks that the status is supplied in the context but that that it's
also used to limit the object_list.
Added check that context dict contains 'tab' before we check its value
so that we get a more helpful message if it's not there.
Deleted irrelevant comment.
Minor readability improvement in
test_feedback_author_is_assigned_on_feedback_create
Added a test to check that a decision's editor is set when the decision
is edited via the django admin screens.
Added new tests to alt_view_test to check that last_status is updated
upon Decision update whether via UI screens or via django admin screens.
Moved code to create and login admin user from
test_decision_editor_set_on_update_via_admin and into a new method on
EconsensusTestCase so that it can be used by other tests and fixed
change_decision_via_admin()'s assertion that the Decision has been
updated successfully in admin screens.
Renamed all org_user_factory variables to org_user - they're not
factories, they are OrganizationUser instances.
Refactored test_active_users_of_org_added_to_watchers_of_new_decision to
make it a bit more readable, and to test when there's more than one
active user for the decision's org.
Checked alt_view_test.py's test_user_can_unwatch_a_decision and removed
inferior duplicate test test_unwatch from decisions_test.py.
Renamed a variable for clarity.