Testing, discussion. Sometimes asthma is easy to spot. You start wheezing and having trouble breathing with exercise or viral illnesses. Or a chronic nighttime cough. However, if you aren't sure, such as a little tight cough after notable exercise, or if you're in the heat a lot, etc, then a visit to your doc can help. Sometimes pulmonary function testing (blowing into a special tube) can show if airflow is normal.
Easy. You have audible wheezing.