public void Add_WhenCalled_ChangesSum()
{
InMemoryCalculator testCalc = MakeTestInMemoryCalculator();
testCalc.Add(1);
int sum = testCalc.FinalSum();
Assert.AreEqual(1, sum);
}
public void Sum_ByDefault_ReturnsZero()
{
// Arrange
InMemoryCalculator testCalc = MakeTestInMemoryCalculator();
// Act
int lastSum = testCalc.FinalSum();
// Assert
Assert.AreEqual(0, lastSum);
}