This paper presents an integrated metamorphic testing environment MTest and reports an experimental analysis of the effectiveness of metamorphic testing, which is carried out using MTest with a real program of sparse matrix multiplication. Quantitative evaluation and comparison of special case testing, metamorphic testing with special and random test cases are illustrated with two measurements: mutation score and fault detection ratio. The case study shows that metamorphic testing and special case testing are complementary to each other, and with respect to source test case for metamorphic testing, random test cases are preferred to special test cases.