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));
        }