GB/T 12085.7-2022 "Optics and photonics — Environmental test methods — Part 7: Drip, rain" describes methods for conducting drip and rain tests on optical and photonic instruments to evaluate their resistance to dripping water or rainfall. The standard covers various severity levels of tests, including drip, constant-rate rainfall, and rainfall accompanied by wind speed. The core testing instrument for implementing this standard is a rain test apparatus, which should be capable of providing controlled drip and rainfall rates. It is typically equipped with a rotating table (rotating at approximately 1–2 revolutions per minute) to simulate spraying from different directions and uses instruments such as a rain gauge to precisely measure the water spray rate to ensure compliance with requirements.