public void GetEmployeeByIDInvalidIDTest()
        {
            // Arrange
            int employeeID = 2;
            List<Employee> employees = new List<Employee>()
            {
                new Employee { ID = 1, FirstName = "Test", LastName = "Test" }
            };

            EmployeeRepository repository = new EmployeeRepository(employees);

            // Act
            Employee result = repository.GetEmployeeByID(employeeID);

            // Assert
            Assert.IsNull(result);
        }
        public void GetEmployeeByIDTest()
        {
            // Arrange
            int employeeID = 1;
            List<Employee> employees = new List<Employee>()
            {
                new Employee { ID = employeeID, FirstName = "Test", LastName = "Test" }
            };

            EmployeeRepository repository = new EmployeeRepository(employees);

            // Act
            Employee result = repository.GetEmployeeByID(employeeID);

            // Assert
            Assert.IsNotNull(result);
            Assert.AreEqual(employees[0], result);
        }