text: const { createFieldUtil } = require('./filed-util')
  
  test('buildSeries()', () => {
      const util = createFieldUtil()
  
      const result1 = util.buildSeries('/no-series')
      expect(result1).toBeNull()
  
      const result2 = util.buildSeries('/my-series/post1')
      expect(result2).toEqual('my-series')
  
      const result3 = util.buildSeries('/my-series/post2/')
      expect(result3).toEqual('my-series')
  })
  