Hi ,do you guys use network language and abbreviations in the test?

I don't. Maybe I'm too old. But I firmly believe that language is a means to communicate with each others, so we must strive to write correctly. Out of respect for the language and the heritage behind. Out of respect for the listener/reader.

Here in France, slang and network languages in essays or whatever other works teachers may give, is forbidden and severely punished by taking out points. (Except if slang is part of the essay, it's a matter of context.)

I don't reply to emails with network language and/or abbreviations. Not only I don't understand most of the content, but also I don't reply to people that don't respect me enough to talk/write to me in a correct language (whether in English or in French).

If I were a teacher, I would be most severe with that. As a student (long ago !), there was NO network language back then and anyway, it was out of question to use them.