How to unit test pseudo elements? -

I have been told from unit testing that CSS has been implemented properly on my element

However CSS refers to these pseudo elements and as far as I know that they are not part of DOM, there is no access to Javascript and therefore I can not test them.

If this was a system test - I could do a CSS regression test with resemblejs, though I need a unit test implementation

How can I apply it with karma? Am + jasmine + angular combo?

David Walsh is a very good answer for this use

Window.getComputedStyle (domElement, ': first') .getPropertyValue (propertyName);