public void TestCompoundShapeMath()
{
// arrange
// manually calc sum of perimeters - line + circle + line
double expectedPerimeterSum = 1 + 18.8495559215387594;
// manually calc sum of areas - line + circle + line
double expectedAreaSum = 0 + 28.274333882308139146;
_compoundShape.Add(_line);
_compoundShape.Add(_circle);
// act
double actualPerimeterSum = _compoundShape.GetPerimeter();
double actualAreaSum = _compoundShape.GetArea();
// assert
Assert.AreEqual(expectedPerimeterSum, actualPerimeterSum);
Assert.AreEqual(expectedAreaSum, actualAreaSum);
}