content: import unittest
  from unittest.mock import patch
  
  from pyecharts.charts import Custom
  from pyecharts.commons.utils import JsCode
  
  
  class TestCustom(unittest.TestCase):
      @patch("pyecharts.render.engine.write_utf8_html_file")
      def test_custom_base(self, fake_writer):
          c = Custom().add(
              series_name="",
              render_item=JsCode(
                  """
                  function (params, api) {
                      var categoryIndex = api.value(0);
                      var start = api.coord([api.value(1), categoryIndex]);
                      var end = api.coord([api.value(2), categoryIndex]);
                      var height = api.size([0, 1])[1] * 0.6;
                      var rectShape = echarts.graphic.clipRectByRect({
                          x: start[0],
                          y: start[1] - height / 2,
                          width: end[0] - start[0],
                          height: height
                      }, {
                          x: params.coordSys.x,
                          y: params.coordSys.y,
                          width: params.coordSys.width,
                          height: params.coordSys.height
                      });
                      return rectShape && {
                          type: 'rect',
                          shape: rectShape,
                          style: api.style()
                      };
                  }
                  """
              ),
              data=None,
          )
          c.render()
          _, content = fake_writer.call_args[0]
          self.assertGreater(len(content), 2000)
          self.assertIn("renderItem", content)
  