For reference, exercise is one of the permitted reasons to leave your home when diagnosed with Covid-19 or when a close contact. Surprised me, but the "Diagnosed Persons and Close Contacts Directions (No 7)" are quite clear: They must take reasonable steps to maintain 1.5 metre distancing, but it is a valid reason. As a result I'd be extremely surprised if people who have taken a test are required to avoid exercise. Actually, I'd expect that legally they are permitted to leave for any of the four reasons, and, while there is a recommendation that they remain on premises, I can't see them having stricter rules than people who have actually been diagnosed.
Of course, I am not recommending leaving your house between test and diagnosis or after diagnosis. Whether legal or not, at minimum you would be laying yourself open to prosecution in the court of public opinion. But when Dan Andrews talked today about fining people who were not present when someone turned up to present their positive test, I'm not sure I can see a basis in the directions for doing that (yet, anyway). The directions for diagnosed persons don't apply to them until a diagnosis has been delivered to them, and even if they did apply, those directions include reasons for leaving the house, including exercise.
OK, story time: I've said earlier in the thread that I am quite able to choose a time and place to walk where I will see no-one. In March I had something, probably flu, that didn't really line up with the then talked about symptoms for Covid-19. As I hadn't returned from overseas, I wasn't eligible for testing, but the expectation was that I didn't have it. On days when I felt I needed a walk and felt up to it, I took a walk. And saw no-one. I would have no problem with anyone waiting for a test result or diagnosed with Covid-19 doing the same, so long as they were suitably careful and it was permitted by the regulations (which currently it seems it is). If health authorities don't want that to happen, they should change the regulations.
One other point: I noticed that today the National Cabinet reaffirmed that suppression, not elimination, was the goal. Though their gold standard for suppression seems to be "no community transmission", which in practical terms is surely close to elimination?