Sandwich testing is a type of testing that consist of two parts,they are Top-down approach and Bottom-up approach.It combines the advantages of both Bottom-up testing and Top-down testing at a time.Bottom-up testing starts from middle layer and goes upward to the top layer where as Top-down testing starts from middle layer and goes downward. Big-bang approach is followed for the middle layer. From this layer bottom-up approach goes upwards and top-down approach goes downwards.
