Testing method and memory module under test

A memory module under test, comprising:

• a memory chip, coupled to an external system;
• wherein the memory module under test is configured to execute operations:
• entering a self-refresh mode respectively in each of a plurality of stages according to each of a plurality of self-refresh commands by the memory chip;
• receiving a first clock enable signal and a first active command in response to a first level of the first clock enable signal to generate a first testing result at a first stage of the stages by the memory chip;
• receiving each of a plurality of second clock enable signals and a second active command in response to the first level of each of the second clock enable signals respectively to generate a second testing result at each of second stages of the stages by the memory chip, wherein a duration time of a second level of the first clock enable signal is smaller than a duration time of the second level of each of the second clock enable signals, wherein each of the first testing result and the second testing results indicates a data state of the memory chip;
• and
• calculating a self-refresh rate according to the first testing result and the second testing results by the external system.