private void FactotialButton_Click(object sender, EventArgs e)
{
CalcFinction s = new CalcFinction();
displayX.Text = Convert.ToString(s.Factorial(Convert.ToInt32(displayX.Text)));
displayY.Clear();
}
public void FactorialTest_x3_expected_6()
{
//arrage
int x = 3;
int expected = 6;
//act
CalcFinction s = new CalcFinction();
double actual = s.Factorial(x);
//assert
Assert.AreEqual(expected, actual);
}