public void TransferAmountBetweenUsers() { var context = serviceProvider.GetRequiredService <DataContext>(); var controller = new BankAccountsController(context); context.BankAccount.Add(bankAccount1); context.BankAccount.Add(bankAccount2); context.SaveChanges(); double initialBalanceBankAccount1 = bankAccount1.Balance; double initialBalanceBankAccount2 = bankAccount2.Balance; string amount = "10"; List <string> transferData = new List <string> { "10", bankAccount1.UserId.ToString(), bankAccount2.UserId.ToString() }; var transferResult = controller.TransferBetweenUsers(transferData); Assert.Equal(initialBalanceBankAccount1 - Single.Parse(amount), bankAccount1.Balance - Single.Parse(amount)); Assert.Equal(initialBalanceBankAccount2 + Single.Parse(amount), bankAccount2.Balance + Single.Parse(amount)); }