public void GetContractorsByPostalCode()
        {
            Mock<IContractorRepository> mock = new Mock<IContractorRepository>();
            mock.Setup(a => a.Contractors).Returns(new Contractor[]
            {
                new Contractor { id = 1, postal_code = "31-987" },
                new Contractor { id = 2, postal_code = "26-110" },
                new Contractor { id = 3, postal_code = "01-585" },
                new Contractor { id = 4, postal_code = "22-151" },
                new Contractor { id = 5, postal_code = "31-987" },
                new Contractor { id = 6, postal_code = "31-987" }
            }.AsQueryable());

            ContractorController ctrl = new ContractorController(mock.Object);
            object[] temp = ctrl.GetContractorsByPostalCode("31-987");
            Assert.AreEqual(temp.Length, 3);
            Assert.AreEqual(((Contractor)temp[2]).id, 6);

            temp = ctrl.GetContractorsByPostalCode("01-585");
            Assert.AreEqual(temp.Length, 1);
            Assert.AreEqual(((Contractor)temp[0]).id, 3);

            temp = ctrl.GetContractorsByPostalCode("11-511");
            Assert.AreEqual(temp.Length, 0);
        }