public void ExampleFailsLiskovSubstitutionPrinciple()
{
// ARRANGE
LiskovSubsitutionPrinciple lsp = new LiskovSubsitutionPrinciple();
// ACT
IList<Rectangle> shapes = lsp.ExampleFailsLiskovSubstitutionPrinciple();
int rectangleArea = shapes[0].GetArea();
int squareArea = (shapes[1] as Rectangle).GetArea();
// ASSERT
Assert.AreEqual(200, rectangleArea);
Assert.AreEqual(100, squareArea);
// Although we have cast to a Rectangle, the subtitution has resulted in the bahviour changing
// as the second object returns the functionality of the Square
}
public void ExamplePassesLiskovSubstitutionPrinciple()
{
// ARRANGE
LiskovSubsitutionPrinciple lsp = new LiskovSubsitutionPrinciple();
// ACT
IList<Shape> shapes = lsp.ExamplePassesLiskovSubstitutionPrinciple();
int rectangleArea = shapes[0].GetArea();
int squareArea = (shapes[1]).GetArea();
// ASSERT
Assert.AreEqual(200, rectangleArea);
Assert.AreEqual(100, squareArea);
// Although we get the same result, each class has different behaviour BUT
// now we don't have the problem of the subclass resutling in different bahviour compared
// to the base class, as the base class is Abstract
}