public async Task TestCreatePaymentForFlatAsync()
        {
            // Arrange
            var payment = new PaymentDTO
            {
                Amount      = 99,
                PaymentType = PaymentType.Other,
                Frequency   = Frequency.Weekly,
                PaidTo      = "Kristina",
                Account     = "111222333",
                StartDate   = new DateTime(2020, 04, 04),
                EndDate     = new DateTime(2020, 05, 05),
                Fixed       = false,
                Description = "food",
            };
            var userIds = new List <int> {
                1, 2
            };

            // Act
            var response = await _paymentsController.CreatePaymentForFlat(payment, userIds);

            // Assert
            Assert.IsInstanceOf <OkObjectResult>(response);
        }