public void AbsoluteValue_ShouldReturnValidResult_ForInt64()
{
// Arrange.
Int64 negativeTwo = -2;
Int64 zero = 0;
Int64 two = 2;
// Act.
var resultOne = negativeTwo.AbsoluteValue();
var resultTwo = zero.AbsoluteValue();
var resultThree = two.AbsoluteValue();
// Assert.
resultOne.Should().Be(2);
resultTwo.Should().Be(0);
resultThree.Should().Be(2);
}