public void AddInterestToBalance()
{
ICustomer customer = new Customer(1, "Name", "Address", "Phone", "Email");
int accNumber = 1;
double initialBalance = 123.45;
IBankAccount account = BankAccount.CreateBankAccount(customer, accNumber, initialBalance);
double interest = initialBalance * account.InterestRate;
DateTime before = DateTime.Now;
account.AddInterest();
DateTime after = DateTime.Now;
Assert.AreEqual(initialBalance + interest, account.Balance);
Assert.AreEqual(1, account.Transactions.Count);
ITransaction t = account.Transactions[0];
Assert.AreEqual(1, t.Id);
Assert.IsTrue(before <= t.DateTime);
Assert.IsTrue(after >= t.DateTime);
Assert.AreEqual("Interest", t.Message);
Assert.AreEqual(interest, t.Amount);
}
