Hi, thanks for your question. What to expect with an STI test is covered at this page which includes an STI check list:
https://smartsexresource.com/get-tested/what-to-expect
One of the tests done for chlamydia and gonorrhea is a urine test and for this test to be accurate, there needs to be at least 1-2 hours between when you have urinated and when the test is done.
Hope this helps. Health Nurse