Metamorphic testing and testing with special values

The problem of testing programs without test oracles is well known. A commonly used approach is to use special values in testing but this is often insufficient to ensure program correctness. This paper demonstrates the use of metamorphic testing to uncover faults in programs, which could not be detected by special test values. Metamorphic testing can be used as a complementary test method to special value testing. In this paper, the sine function and a search function are used as examples to demonstrate the usefulness of metamorphic testing. This paper also examines metamorphic relationships and the extent of their usefulness in program testing.