CalculatorTests.cs

public class CalculatorTests
{
    readonly Calculator calculator;

    public CalculatorTests()
    {
        calculator = new Calculator();
    }

    [Input(2, 3, 5)]
    [Input(3, 5, 8)]
    public void ShouldAdd(int a, int b, int expectedSum)
    {
        calculator.Add(a, b).ShouldEqual(expectedSum);
    }

    [Input(5, 3, 2)]
    [Input(8, 5, 3)]
    [Input(10, 5, 5)]
    public void ShouldSubtract(int a, int b, int expectedDifference)
    {
        calculator.Subtract(a, b).ShouldEqual(expectedDifference);
    }
}