TEST

public class CalculatorTests
{
    [Fact]
    public void AddTest()
    {
        Assert.Equal(4, Calculator.Add(2, 2));
    }

    [Fact]
    public void SubtractTest()
    {
        Assert.Equal(1, Calculator.Subtract(3, 2));
    }

    [Theory]
    [InlineData(3)]
    [InlineData(5)]
    public void IsOddWhenTrue(int value)
    {
        Assert.True(Calculator.IsOdd(value));
    }

    [Theory]
    [InlineData(2)]
    [InlineData(4)]
    public void IsOddWhenFalse(int value)
    {
        Assert.False(Calculator.IsOdd(value));
    }
}