Made sure connections are actually closed in backends tests

            # connections[DEFAULT_DB_ALIAS] does.

            from django.db import connections

            connection = connections[DEFAULT_DB_ALIAS]

            # Allow thread sharing so the connection can be closed by the

            # main thread.

            connection.allow_thread_sharing = True

            connection.cursor()

            connections_set.add(connection)

        for x in range(2):

        # connection opened in the main thread will automatically be closed on

        # teardown).

        for conn in connections_set:

            if conn != connection:

            if conn is not connection:

                conn.close()

    def test_connections_thread_local(self):

        # connection opened in the main thread will automatically be closed on

        # teardown).

        for conn in connections_set:

            if conn != connection:

            if conn is not connection:

                conn.close()

    def test_pass_connection_between_threads(self):