Just make sure you don't do you slin injects before bed.
Now, if you're the type to get excited due to the injection, it may keep you up a bit longer. Personally I do my inject prior to working out, which is night time. Test levels should have nothing to do with keeping you up, it should be fairly consistant if you're doing it right. The only factor should be the excitable thing.
Give it a go and let us know.