To answer your original question - who can conduct a swim test for a unit swim - Any conscientious adult who is familiar with basic swimming strokes and who understands and abides by the guidelines can administer the test. The guidelines being the statement of the swimmer test -
Jump feet first into water over the head, level off, and begin swimming. Swim 75 yards in a strong manner using one or more of the following strokes: side, breast, trudgen, or crawl; then swim 25 yards using an easy, resting backstroke. The 100 yards must be completed without stops and must include at least one sharp turn.
After completing the swim, rest by floating.
Now to the other question - who can give a pre camp swim test for summer camp - Aquatics Instructor, BSA; Cub Scout Aquatics Supervisor; BSA Lifeguard; certified (Red Cross, YMCA or other similar certification) lifeguard; swimming instructor; or swim
coach - however - the camp aquatics director can accept or reject any or all of the swimmers for whatever reason - and have everyone redo the test at camp. He/She has the final word.