public void ValideSiblings() { Person father = new Person("King Shan", "Male", ListOfRelations); Person mother = new Person("Queen Anga", "Female", ListOfRelations); Relationship spouse = new Relationship(father, mother, "Spouse"); ListOfRelations.Add(spouse); Person child1 = new Person("Chit", "Male", ListOfRelations); Relationship relation1 = new Relationship(mother, child1, "Child"); ListOfRelations.Add(relation1); Person child2 = new Person("Ish", "Male", ListOfRelations); Relationship relation2 = new Relationship(mother, child2, "Child"); ListOfRelations.Add(relation2); Person child3 = new Person("Vich", "Male", ListOfRelations); Relationship relation3 = new Relationship(mother, child3, "Child"); ListOfRelations.Add(relation3); List <String> siblings = child1.Sibling(null); Assert.AreEqual(siblings[0], "Ish"); Assert.AreEqual(siblings[1], "Vich"); }