If this value is generated by your code then test the piece of code that is generating it's value, not the cookie itself. So if you want to test is the Laravel setting the cookie correctly don't do it. First reason is that you shouldn't test what you don't own. Second reason is that Laravel is used by bunch of developers and companies, and if something was broken there it would be noticed pretty fast and fixed even faster.
This returns a long string made of two sub strings separated by a pipe. The right sub string is the value i set in the cookie. I'm not sure what the left one is yet...