DIT085 Ed 2015 Practical Phase 1

The first phase of this project concerns test-driven development of the kernel of our WhatsUpGU server. Before we start test-driven development, we need to fix the interface of the to-be-implemented module, which should provide the following functionalities:

• Add: adding a string message from a given Id (the sender's telephone number) for a given ID (the recipients telephone number); the message is supposed to be stored at the server side until it is fetched by the recipient. For simplicity, we assume that the message is stored in the memory. Upon successful addition of the message a unique positive integer as the identifier of the added message is returned; upon failure a value indicating error (0 or a negative number is returned).

• Delete: the sender of the message can request for removing the message before it is fetched by the recipient.

• Replace:

• Fetch: