code: def test_wordcloud_shapes(fake_writer):
      c = WordCloud().add(
          "", words, word_size_range=[20, 100], shape="cardioid"
      )
      c.render()
      _, content = fake_writer.call_args[0]
      assert_equal(c.theme, "white")
      assert_equal(c.renderer, "canvas")
  
file_path: pyecharts/test/test_wordcloud.py
imports: from unittest.mock import patch
  from nose.tools import assert_equal, assert_in
  from pyecharts.charts import WordCloud
  from pyecharts.commons.utils import JsCode
  from pyecharts.exceptions import WordCloudMaskImageException
label_desc: Use image node_id 2 for calling a global function with example usage: test_wordcloud_shapes(fake_writer) without return types