If you are in the middle of a hyperglycemia attack would it be best to get an accurate test on the severity of it? Is there home tests?

Yes, but... Of course there are home tests for blood glucose levels which can tell you how high your glucose is...And you can take extra insulin, if that's what you have, as advised or recommended for that glucose level. But an acute "attack" probably deserves the attention of you primary care physician, endocrinologist, or, if necessary, an emergency room. This is not something to trifle with, it can kill.
Hyperglycemia. It is unclear what is meant by a hyperglycemia "attack". Conventional glucometers do not accurately measure glu above about 450, and simply read "high". If you are diabetic, and your glu reads "high", then you need to do something, eg take more insulin, or see your doctor. Whether your glu is 450, 550, 650, etc is less important, since it is clear you need to do something.