public void Can_Add_Contractors_To_BuildingManager() { // Arrange LegalPerson legalPersonForContractor1 = new LegalPerson("12345678902", "Contractor 1 d.o.o."); Contractor contractor1 = new Contractor(legalPersonForContractor1); LegalPerson legalPersonForContractor2 = new LegalPerson("12345678903", "Contractor 2 d.o.o."); Contractor contractor2 = new Contractor(legalPersonForContractor2); Contractor[] contractors = new Contractor[] { contractor1, contractor2 }; LegalPerson legalPersonForContractor3 = new LegalPerson("12345678904", "Contractor 3 d.o.o."); Contractor contractor3 = new Contractor(legalPersonForContractor3); LegalPerson legalPersonForManager = new LegalPerson("12345678901", "Mile d.o.o."); // Act BuildingManager buildingManager = new BuildingManager(legalPersonForManager, contractors); buildingManager.AddContractor(contractor3); // Assert Assert.AreEqual(3, buildingManager.Contractors.Count); Assert.AreEqual(contractor1, buildingManager.Contractors.ElementAt(0)); Assert.AreEqual(contractor2, buildingManager.Contractors.ElementAt(1)); Assert.AreEqual(contractor3, buildingManager.Contractors.ElementAt(2)); }