There is now a placement.base.TestCase for placement functional tests
which assembles the necessary configuration and fixtures. This change
uses that base class in the db functional tests and extends the base
class as required to add all the necessary functionality.
In the process issues were exposed in the fixtures.gabbits use of
oslo_config (causing tests to fail based on fallout from changes
elsewhere in the functional tests) so this change also fixes that
and limits the gabbi tests to only caring about the placement database
connection, which is more correct and how it should have been all
along.
This change removes the ConfPatcher fixture in fixtures.placement
because it is no better than using the oslo_config provided
fixture and was in the way while diagnosing difficulties with
getting these changes to work correctly.
The root cause of those problems was that placement changes were
at cross purposes with how the nova.tests.fixtures.Database fixture
expects to work: The goal of these changes was to only configure
and establish those fixtures that were strictly necessary for
placement in the placements tests. However, when _any_ database
is requested from the Database fixture, the context managers for
all of them are configured.
This means, for example, that if a placement fixture, which
originally was not configuring a 'connection' string for the api
or main databases, ran before a later api db fixture, the api db
fixture would fail with no connection string available.
The quick and dirty fix is used here to fix the problem: we set
reasonable configuration for all three databases in the placement
tests that need the placement database fixture.
In the future when placement is extracted, these problems go away
so it does not seem worth the effort (at least not now) to
restructure the nova Database fixture.
blueprint: placement-extract
Change-Id: Ice89e9a25f74caaa53b7df079bd529d172354524
f5783d90bc