First round hr general interview.

Then I got links to complete a hacker rank test based on design rest based stat system.

Some of the requirements were not depicted properly .No matter how beautifully you designed things,if you miss even a slightest part,you will be rejected .In my case I was told transaction was not taken care of,I didn't take since it was not part of requirements.pls don't waste your weekend on this test

I need to design a REST based stat system.