Brother as far as the written test is concerned so it is not going to held on the same day u will just have to qualify physical test which consists of height and chest measurement nothing else............. after that u will be free to go home For written test u will be invited through another letter and it is most probably expected to be arranged in a month or two....... One of my friend is ASP and i got this info from him for my cousin.......
The promotion process is rapid compare to Rankers .. one will just have to wait for three years(including one year of training) to become Sub-Inspector

Work hard and inshallah u will get through it...........

Best of luck..............

Plz remember me in your prayers..............

regards.........