Have mild fever. not sure if its related to covid and if a test needs to be done. how long does test take?

Basics: The persons who definitely need the test are those with difficulty/pain with breathing or exertion. The rest would be determined by multiple factors not provided in the post (region,local covid activity,job.etc.). Test turn around time varies with the type done & could vary from minutes to several days. You need to consult the local health department for most of this information.

COVID 19 concerns: Do you only have one symptom? Suspicion for COVID 19 is higher if you have at least 2 of these symptoms: temp of at least 99.6, Cough, Shortness of breath, Chills, Shivering, Muscle pain, Headache, Sore throat or new loss of taste or smell. If you have more than 1 sx - may need med consult for testing referral depending on where you live.