code: def test_file_memory_node():
      mem = FileMemory(filename, tree_conf)
  
      with pytest.raises(ReachedEndOfFile):
          mem.get_node(3)
  
      mem.set_node(node)
      assert node == mem.get_node(3)
  
      mem.close()
  
imports: import io
  import os
  import platform
  from unittest import mock
  import pytest
  from bplustree.node import LeafNode, FreelistNode
  from bplustree.memory import FileMemory, open_file_in_dir, WAL, ReachedEndOfFile, write_to_file
  from bplustree.const import TreeConf
  from .conftest import filename
  from bplustree.serializer import IntSerializer
label_desc: Use image node_id 1 for calling a global function with example usage: test_file_memory_node() without return types