Technically, you don't need to read or pass any test to serve in Congress. According to the U.S. Constitution, the eligibility requirements for Congress are straightforward: for the House of Representatives, a person must be at least 25 years old, have been a U.S. citizen for at least seven years, and live in the state they represent; for the Senate, a person must be at least 30 years old, have been a U.S. citizen for at least nine years, and live in the state they represent (U.S. Const. art. I, §§ 2–3). While all members take an oath to support and defend the Constitution (5 U.S.C. § 3331), there is no legal requirement that they read or pass a test on it before taking office. It is ultimately up to the voters to decide if a candidate is knowledgeable and qualified.