Disclosed are a test apparatus and a testable asynchronous circuit. The test apparatus includes: a first input end, a second input end, a third input end, a fourth input end, a fifth input end, a first selector, a second selector, a D flip-flop, and a first output end. The first input end is configured to input a data signal or a test result of a previous circuit under test; the second input end is configured to input a test excitation signal or a test result that is output by a previous test apparatus; the third input end is configured to input a clock signal; the fourth input end is configured to input a selection signal; and the fifth input end is configured to input a selection signal.