Test method for memory device, operation method of test device testing memory device, and memory device with self-test function

A test method for a memory device including a plurality of memory cells includes generating a first test pattern, performing a first pattern write operation of writing the first test pattern in the plurality of memory cells, reading first data from the plurality of memory cells in which the first test pattern was written, generating a second test pattern based on the first data, and performing a second pattern write operation of writing the second test pattern in the plurality of memory cells. The second test pattern is generated such that a write operation is skipped with regard to failure cells from among the plurality of memory cells at which a write failure occurs, during the second pattern write operation.