Testing techniques

Teste unitário

O contrato de uma stack

Verifying the unit contract

• A stack is empty on construction.

• A stack has size 0 on construction.

• After n pushes to an empty stack, n > 0, the stack is not empty && its size is n.

• If one pushes x then pops, the value popped is x, the size is decreased by one.

• If one pushes x then peeks, the value returned is x, but the size stays the same.

• If the size is n, then after n pops, the stack is empty and has a size 0.

• Popping from an empty stack does throw a NoSuchElementException.

• Peeking into an empty stack does throw a NoSuchElementException.

• For bounded stacks only, pushing onto a full stack does throw an IllegalStateException.