A test circuit for testing a memory is provided. The input of the memory is coupled to a register, and the register is coupled to a logic circuit. The test circuit includes a first test register group, a second test register group, a first multiplexer, and multiple second multiplexers. The first test register group includes at least one test register. The second test register group includes at least one test register. The first multiplexer is coupled between the first test register group and the register. The second multiplexers are coupled between the second test register group and the register.