Any sort of test to detect if someone got caught COVID-19 in his life?

I am wondering if in the future there will be some sort of test for detecting COVID-19 traces (anti bodies etc.) to ensure that the person has caught and survived COVID-19.
My friend has a weird dry cough that won’t go away. I have no fever; absolutely not at all! 2-3 days ago I had a very very very light sore throat. Not feeling weak, fatigue or tired at all. He is in a city in Germany where only 2 cases have been confirmed at max. He is self isolating.
We wouldn’t want to die without learning whether it is some sort of cold virus or COVID-19.
Can anti bodies exist in blood etc. for years? If yes, there might be some hope. Does it depend on the virus or bacterial how long they will stay in the blood or in the person´s body?

Antibodies themselves are short lived but memory B cells that produce antibodies can last for decades. But nothing lasts forever and this includes cells.

If you get tested within let’s say 10-15 years, a simple antibody test will show whether you’ve ever been infected or not. If you wait longer, those memory B cells will die off, forgetting how to make those antibodies, and you many never know if you were infected in the past.

Several countries have already developed this kind of blood test. As far as I know, the CDC is working on it but is not ready yet.