我有一个使用BlazeJS的Meteor项目。我正在为Mocha中的该项目编写测试用例以进行渲染。我面临以下错误： -
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)
请告知我如何解决上述错误。