Hi sir,
I'm not native English speaker, but I really am good at English. I'm from Egypt.
I've been studying English for about 11 years now. My studies in college were also in English.
More over, I've been online working on the affiliate marketing niche for about 2 years now, dealing with native English speakers from all over the world, Australia, Malaysia,US,UK,Canada. I have people from all of these countries in front of me on Skype several hours a day working together on our campaigns. Meaning that I know the culture and the way of thinking they have. And that's it, that's what learning a new language is all about, it's just about practicing with someone who got the accent and who can simulate the culture and way of thinking. A little test won't do bad for you though.
Thanks in advance