smart unit test in visual studio 2015

Question

when i want to create a smart unit test in visual studio 2015 then it show error which is:

The selected type is not visible and can not be expolred / can not run test for selected type because type is not visible.

my code is this.

class Program

{

public static void cal(int n1, int n2, out int add, out int sub, out int mul, out float div)

{

add = n1 + n2;

sub = n1 - n2;

mul = n1 * n2;

div = (float)n1 / n2;

}

static void Main(string[] args)

{

int n1, n2;

int add, sub, mul;

float div;

Console.Write("Enter 1st number");

n1 = Convert.ToInt32(Console.ReadLine());

Console.Write("\nEnter 2nd number");

n2 = Convert.ToInt32(Console.ReadLine());

Program.cal(n1, n2, out add, out sub, out mul, out div);

Console.WriteLine("\n\n{0} + {1} = {2}", n1, n2, add);

Console.WriteLine("{0} - {1} = {2}", n1, n2, sub);

Console.WriteLine("{0} * {1} = {2}", n1, n2, mul);

Console.WriteLine("{0} / {1} = {2}", n1, n2, div);

Console.ReadLine();

}

}

 

 when i goes on method right click on it create the smart unit test then it show the error.

please help me.

Thanking you