ember-cli-blanket not working

I have installed the plugin for 'ember-cli-blanket', using command:

ember install:addon ember-cli-blanket0

But when I run the tests using "http://localhost:4200/tests", nothing is loading I am getting just a blank page, no error in console also. When I referred in some online tutorials, they asked to pass "data-cover" with the <script></script> tag. But no progress. If i uninstall the plugin and run the tests it is working fine.

Can anyone tell what am I doing wrong or any more settings needs to be done?