Getting error while writing test case for template rendering in Mocha

Hi,

I have an Meteor project using BlazeJS. I am writing test case for that project in Mocha for rendering. And i am facing below error:-

Error: No such function: _
  at blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:3214
  at Spacebars.call (spacebars.js?hash=ebf9381e7fc625d41acb0df14995b7614360858a:172)
  at Spacebars.mustacheImpl (spacebars.js?hash=ebf9381e7fc625d41acb0df14995b7614360858a:106)
  at Object.Spacebars.mustache (spacebars.js?hash=ebf9381e7fc625d41acb0df14995b7614360858a:110)
  at Blaze.View._render (app.js?hash=5f5e88169d987fce5c1c7e49f67c237d33b43cb9:514)
  at Blaze.View.doRender (blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:2086)
  at blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:1934
  at Function.Template._withTemplateInstanceFunc (blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:3744)
  at blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:1932
  at Object.Blaze._withCurrentView (blaze.js?hash=f33d3dfed63a491d24e3aa07ad66c24b5fe8c761:2271)

Please advise how i resolved above error.

Thanks & Regards,
Saransh