Yes, there was a lung function test on my medical and for gods sake, make sure you mention your Asthma. One of the parts of the medical is a urine sample that is sent away for testing (for drugs etc). Don't mess your chances up by not declaring that you are taking medication (inhalers) for a pre existing condition. Whether or not the test would pick up your inhalers is immaterial really. The nurse doing the medical is impartial and just collects the results, so be upfront about it.