First, if you desire to be a cop, deputy, or to enter the academy, your daily routine should have some physical fitness training in it.
Next, know the requirements that your target agency requires for its entrance exam, its academy fitness standards, and the physical requirements for tenure. Whining and crying "I did not know" is not going to buy you any pity points. We do not give out runner-up awards.
Once you know the standards of the test, study them and ask yourself these questions: Can I do this now? and How can I improve my passing score?
If this is the standard run, press, push-up test, get into the gym for strength training and do some serious track work. Again, start preparing and train up to the tests. Just because you ran track in high school does not mean you can do it now. This style of testing is all elements at one session, so train that way. Running on Monday and practicing push-ups on Wednesday does not cut it. Train as you would test.
And do your homework. Find out if this agency gives an agility test or a job-task related test? Read and study how you can recreate the test and train for it.