python - Flask unit tests with SQLAlchemy and PostgreSQL exhausts db connections -

i'm running suite of straightforward test cases using flask, sqlalchemy, , postgresql. using application factory, i've defined base unit test class so:

class basetestcase(unittest.testcase):     def setup(self):         self.app = create_app()         self.app.config.from_object('app.config.test')         self.api_base = '/api/v1'          self.ctx = self.app.test_request_context()         self.ctx.push()          self.client = self.app.test_client()         db.create_all()      def teardown(self):         db.session.remove()         db.drop_all(app=self.app)         print db.engine.pool.status()         if self.ctx not none:             self.ctx.pop() 

all goes few unit tests, until:

operationalerror: (operationalerror) fatal:  remaining connection slots reserved non-replication superuser connections 

it seems there 1 connection in pool (db.engine.pool.status() each test shows: pool size: 5 connections in pool: 1 current overflow: -4 current checked out connections: 0), somehow app never disconnects. new app instance created each test case, seems fine according documentation. if move app creation module level works fine.

does know why happening?

thanks

add db.get_engine(self.app).dispose() after db.drop_all()