public void Add_PositiveNumbersToList_FirstIndexValue()
{
//Arrange
Addition add = new Addition();
int firstValue = 4;
int secondValue = 5;
int expected = 4;
int actual;
//Act
add.AddNumbersToList(firstValue, secondValue);
actual = add.myNumbers[0];
//Assert
Assert.AreEqual(expected, actual);
}