async def test_connection_pool_blocks_until_conn_available(self, master_host):
        """
        When out of connections, block until another connection is released
        to the pool
        """
        connection_kwargs = {"host": master_host}
        pool = self.get_pool(
            max_connections=1, timeout=2, connection_kwargs=connection_kwargs
        )
        c1 = await pool.get_connection("_")

        async def target():
            await asyncio.sleep(0.1)
            await pool.release(c1)

        start = asyncio.get_event_loop().time()
        await asyncio.gather(target(), pool.get_connection("_"))
        assert asyncio.get_event_loop().time() - start >= 0.1

        When out of connections, block until another connection is released
        to the pool
        
tests/test_connection_pool.py