单元测试grails标记

package com.example

class MyTagLib {
  def listTrees = {attrs ->
    List<TreeDto> allTrees = getMandatoryAttributeValue(attrs, \'trees\')
    out << g.select(from: allTrees)
  }
}

g

protected void setUp() {
    super.setUp()
    mockTagLib(FormTagLib)
    def g = new FormTagLib()
    tagLib.metaClass.g = g
}