def test_add(self):
        prio_set_list = event._PrioritizedSetList()
        objs = [(i,) for i in range(5)]

        prio_set_list.add(0, objs[0])
        assert prio_set_list.list == [(0, {objs[0]})]

        prio_set_list.add(0, objs[1])
        assert prio_set_list.list == [(0, {objs[0], objs[1]})]

        prio_set_list.add(10, objs[2])
        assert prio_set_list.list == [(10, {objs[2]}),
                                      (0,  {objs[0], objs[1]})]

        prio_set_list.add(-10, objs[3])
        assert prio_set_list.list == [( 10, {objs[2]}),           # noqa: E201
                                      (  0, {objs[0], objs[1]}),  # noqa: E201
                                      (-10, {objs[3]})]
        prio_set_list.add(-1, objs[4])
        assert prio_set_list.list == [( 10, {objs[2]}),           # noqa: E201
                                      (  0, {objs[0], objs[1]}),  # noqa: E201
                                      ( -1, {objs[4]}),           # noqa: E201
                                      (-10, {objs[3]})]
def from_envvar(self, variable_name: str, silent: bool = False) -> bool:
        """Loads a configuration from an environment variable pointing to
        a configuration file.  This is basically just a shortcut with nicer
        error messages for this line of code::

            app.config.from_pyfile(os.environ['YOURAPPLICATION_SETTINGS'])

        :param variable_name: name of the environment variable
        :param silent: set to ``True`` if you want silent failure for missing
                       files.
        :return: bool. ``True`` if able to load config, ``False`` otherwise.
        """
        rv = os.environ.get(variable_name)
        if not rv:
            if silent:
                return False
            raise RuntimeError(
                f"The environment variable {variable_name!r} is not set"
                " and as such configuration could not be loaded. Set"
                " this variable and make it point to a configuration"
                " file"
            )
        return self.from_pyfile(rv, silent=silent)