text: 
  const tx2 = require('..')
  const should = require('should')
  
  describe('Metric', function() {
    this.timeout(4000)
  
    it('should register a metric', () => {
      tx2.metric({
        name: 'test',
        val: () => {
          return 20
        }
      })
    })
  
    it('should metric exists', () => {
      should(tx2.metricExists('test')).eql(true)
    })
  
    it('should unknown metric not exists', () => {
      should(tx2.metricExists('unknowsss')).eql(false)
    })
  
    it('should have metric present', (done) => {
      tx2.once('data', (dt) => {
        should(dt.type).eql('axm:monitor')
        should(dt.data.test.value).eql(20)
        done()
      })
    })
  
    it('should register metric v2', () => {
      tx2.metric('test2', () => {
        return 30
      })
    })
  
    it('should have metric present', (done) => {
      tx2.once('data', (dt) => {
        should(dt.type).eql('axm:monitor')
        should(dt.data.test2.value).eql(30)
        done()
      })
    })
  
    it('should register metric v3', () => {
      let m = tx2.metric('test3', 0)
      m.set(45)
    })
  
    it('should have metric present', (done) => {
      tx2.once('data', (dt) => {
        should(dt.type).eql('axm:monitor')
        should(dt.data.test3.value).eql(45)
        done()
      })
    })
  
  })
  