public void ProveThatPolymorphismIsApparent()
{
Tiger tiger = new Tiger();
Frog frog = new Frog();
Animal bird = new Bird();
string expectedTiger = "food";
string expectedFrog = "Bugs";
string expectedBird = "Dirt and stuff";
Assert.Equal(expectedTiger, tiger.Diet());
Assert.Equal(expectedFrog, frog.Diet());
Assert.Equal(expectedBird, bird.Diet());
}