Both the US Citizenship Test and the Naturalization interview take place at the same time. Both are the same. When you go for the interview, the USCIS officer will ask you questions on your background, eligibility, why you want to become a citizen, etc. after that, you will be asked verbal questions related to the citizenship test. This means that unless you have to attend a re-examination because of a low score, you only need to attend one interview.