pithos: Destroy test database after test execution

:
Pithos uses a pool for the backend objects.
Pooled backend objects override the default close behavior
and return the object to the pool instead.
Therefore, django was unable to destroy the database
since there were active connections.
Therefore, we force the pool to shutdown before
the django attempts to destroy it.

snf-pithos-app/pithos/api/test/__init__.py

@@ -144,6 +144,12 @@ class PithosTestSuiteRunner(DjangoTestSuiteRunner):
         prepate_db_connection()
         return old_names, mirrors
 
+    def teardown_databases(self, old_config, **kwargs):
+        from pithos.api.util import _pithos_backend_pool
+        _pithos_backend_pool.shutdown()
+        super(PithosTestSuiteRunner, self).teardown_databases(old_config,
+                                                              **kwargs)
+
 
 class PithosAPITest(TestCase):
     def setUp(self):

snf-pithos-backend/pithos/backends/lib/sqlalchemy/dbwrapper.py

@@ -64,6 +64,7 @@ class DBWrapper(object):
 
     def close(self):
         self.conn.close()
+        self.conn = None
 
     def execute(self):
         self.trans = self.conn.begin()

snf-pithos-backend/pithos/backends/util.py

@@ -151,6 +151,14 @@ class PithosBackendPool(ObjectPool):
         backend.messages = []
         return False
 
+    def shutdown(self):
+        while True:
+            backend = self.pool_get(create=False)
+            if backend is None:
+                break
+            self.pool_put(None)
+            backend._real_close()
+
 
 def _pooled_backend_close(backend):
     backend._pool.pool_put(backend)