could use some unit tests...

[jakefreeberg]

I should really contribute them myself, but if you put any more effort into this example, I think some unit tests that show how to spy on the global ga() would save people some time.

I ended up copying the approach they use here: https://github.com/angulartics/angulartics2/blob/35921ff55471c58db4b255145d259acb83e088ee/src/providers/ga/angulartics2-ga.spec.ts