Test is really important in teaching and learning English, not only with school children but also with all other types of learners It is no double that test is a useful way for teachers to base on and measure their students’ abilities or what they have gained in a period of learning. From the result of the test, the teachers themselves evaluate the effectiveness of their teaching and adjust it, if necessary, to make it more suitable and efficient. Moreover, it is also a good way that shows the learners how much they have achieved and motivates them much in the learning process. Being an essential method to assess but writing a good test is not easy. It is indeed quite a challenge and it requires lots of patience and experience, and it takes a degree of trail and error. In order to design a good test, we have to know much about the theory, the rules of it. Since being aware of the importance of test and the difficulties in designing a good test, I want to spend time researching this topic so that I can understand more about it, then I can apply it effectively in my teaching career.