Flask unittest and sqlalchemy using all connections

flask, flask-sqlalchemy, postgresql, sqlalchemy

Solution

I found the answer here -- https://stackoverflow.com/a/17998485/1870623 and a great explination here -- https://stackoverflow.com/a/16390645/1870623

The solution is to add `db.get_engine(self.app).dispose()` to the tearDown()

class TestCase(Base):
    def setUp(self):
        db.create_all()

    def tearDown(self):
        db.session.remove()
        db.drop_all()
        db.get_engine(self.app).dispose() # This

Problem

I've just run into an issue running unittests on my flask app after I had roughly 100 unittests. All unittests will pass, but when run all at once they will fail with the following error: ``` OperationalError: (OperationalError) FATAL: remaining connection slots are reserved for non-replication superuser connections ``` Everything is running in a virtualbox/vagrant/ubuntu12.04 instance on local machine. My postgres max_connections is set to 100 so I'm assuming that the connections aren't closing and after running 100 tests I use up all the available ones. This person Flask unit tests with SQLAlchemy and PostgreSQL exhausts db connections looks like they are having the same exact problem. Mike/Zzzeek (sqlalchemy dev) even responded to it saying that something may be happening in create_app() so I've included that as well below. Does this mean I'm not closing my connections somewhere? All of these errors are triggered by `db.create_all()` in my setUp() method of my unittest. # test.py ``` class TestCase(DataMixin, Base): """Base test class""" def create_app(self): return create_app(TestConfig()) def setUp(self): db.create_all() def tearDown(self): db.session.remove() db.drop_all() ``` # app.py ``` def create_app(config=None): app = Flask(__name__) # Config app.config.from_object(BaseConfig()) if config is not None: app.config.from_object(config) # Extensions db.init_app(app) mail.init_app(app) bcrypt.init_app(app) # Blueprints app.register_blueprint(core_blueprint, url_prefix='/') app.register_blueprint(accounts_blueprint, url_prefix='/account') app.register_blueprint(admin_blueprint, url_prefix='/admin') app.register_blueprint(cart_blueprint, url_prefix='/cart') # Login Manager login_manager.setup_app(app, add_context_processor=True) login_manager.login_view = "accounts.login" login_manager.user_callback = load_user # Templates app.jinja_env.globals['is_admin'] = is_admin app.jinja_env.globals['is_staff'] = is_staff @app.context_processor def inject_cart(): cart = count = None if current_user.is_authenticated(): cart = current_user.get_cart() return dict(cart=cart) # Error Handling @app.errorhandler(404) def page_not_found(error): return render_template('404.html'), 404 return app ```

Original source