Meteor testing with mocha/chai - ReactiveVars/HighCharts

HI Team,
I would like to test meteor using mocha/chai library without using meteor package practicalmeteor:mocha.
Could import the module and load the test from tests folder.

Current issues which are making the import not loaded are using ReactiveVar and HighCharts module.

Is there any way to testdouble the ReactiveVar calls and HighChart.chart calls from the mocha tests.
Otherwise the meteor calls can be testdoubled and the results can be checked with in test cases.