code: def test_graph_base_v1(fake_writer):
      nodes = [
          opts.GraphNode(name="结点1", symbol_size=10),
          opts.GraphNode(name="结点2", symbol_size=20),
          opts.GraphNode(name="结点3", symbol_size=30),
          opts.GraphNode(name="结点4", symbol_size=40),
          opts.GraphNode(name="结点5", symbol_size=50),
      ]
      links = [
          opts.GraphLink(source="结点1", target="结点2"),
          opts.GraphLink(source="结点2", target="结点3"),
          opts.GraphLink(source="结点3", target="结点4"),
          opts.GraphLink(source="结点4", target="结点5"),
          opts.GraphLink(source="结点5", target="结点1"),
      ]
      c = (
          Graph()
          .add("", nodes, links, repulsion=4000)
          .set_global_opts(
              title_opts=opts.TitleOpts(
                  title="Graph-GraphNode-GraphLink"
              )
          )
      )
      c.render()
      _, content = fake_writer.call_args[0]
      assert_equal(c.theme, "white")
      assert_equal(c.renderer, "canvas")
  
file_path: pyecharts/test/test_graph.py
imports: import os
  import json
  from unittest.mock import patch
  from nose.tools import assert_equal, assert_in
  from pyecharts import options
  from pyecharts.charts import Graph
label_desc: Use image node_id 2 for calling a global function with example usage: test_graph_base_v1(fake_writer) without return types