content: import unittest
  from unittest.mock import patch
  
  from pyecharts import options as opts
  from pyecharts.charts import ThemeRiver
  
  
  class TestThemeRiverChart(unittest.TestCase):
      @patch("pyecharts.render.engine.write_utf8_html_file")
      def test_themeriver_basefake_writer(self, fake_writer):
          data = [
              ["2015/11/08", 10, "DQ"],
              ["2015/11/20", 30, "TY"],
              ["2015/11/08", 21, "SS"],
              ["2015/11/14", 7, "QG"],
              ["2015/11/22", 4, "SY"],
              ["2015/11/20", 26, "DD"],
          ]
          c = ThemeRiver().add(
              ["DQ", "TY", "SS", "QG", "SY", "DD"],
              data,
              singleaxis_opts=opts.SingleAxisOpts(type_="time", pos_bottom="10%"),
          )
          c.render()
          _, content = fake_writer.call_args[0]
          self.assertEqual(c.theme, "white")
          self.assertEqual(c.renderer, "canvas")
  