static void Main(string[] args)
{
int n = 5;
Sum s = new Sum();
int result = s.sum(n);
System.Console.WriteLine(result.ToString());
}
public void TestSum_from_1_to_zero()
{
Sum s = new Sum();
int n = 0;
int actual = s.sum(n);
int expected = 1;
Assert.AreEqual(expected, actual);
}
public void TestSum_from_1_to_minus_4()
{
Sum s = new Sum();
int n = -4;
int actual = s.sum(n);
int expected = -9;
Assert.AreEqual(expected, actual);
}