You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: tc_data_source.rb
    path of file: ./repos/caxlsx/test/drawing
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

require 'tc_helper'

class TestNumDataSource < Minitest::Test
  def setup
    @data_source = Axlsx::NumDataSource.new data: ["1", "2", "3"]
  end

  def test_tag_name
    assert_raises
    
  def test_to_xml_string_strLit
    str = +'<?xml version="1.0" encoding="UTF-8"?>'
    str << '<c:chartSpace xmlns:c="' << Axlsx::XML_NS_C << '">'
    str << @data_source.to_xml_string
    doc = Nokogiri::XML(str)

    assert_equal(1, doc.xpath("//c:val").size)
  end
end