Have you come into contact with anyone who might be ill right now? Were you in contact with this person for some time (more than 15 minutes) and up close (within a distance of 1.5 metres)? (For example: a housemate, a colleague sitting next to you in the office, a friend from school). This is known as higher-risk of being infected.
If you have a high-risk contact, you should not have a covid test done.
You can do a self-test and follow this precautions. Click here for an overview.