karma-nghtml2js preprocessor

[ilanbiala]

When testing AngularJS directives with external template URLs, https://docs.angularjs.org/guide/unit-testing at the bottom recommends using karma-nghtml2js to handle loading in the templates, but many of the guides seem to conflict and the plugin itself has very little documentation. Can an example be added here of how to use the plugin properly to easily test more complex directives?