public class BankAccountTests { [Fact] public void Newly_opened_account_has_zero_balance() { var account = new BankAccount(); account.Open(); Assert.Equal(0m, account.Balance); } [Fact(Skip = "Remove this Skip property to run this test")] public void Single_deposit() { var account = new BankAccount(); account.Open(); account.Deposit(100m); Assert.Equal(100m, account.Balance); } [Fact(Skip = "Remove this Skip property to run this test")] public void Multiple_deposits() { var account = new BankAccount(); account.Open(); account.Deposit(100m); account.Deposit(50m); Assert.Equal(150m, account.Balance); } [Fact(Skip = "Remove this Skip property to run this test")] public void Withdraw_once() { var account = new BankAccount(); account.Open(); account.Deposit(100m); account.Withdraw(75m); Assert.Equal(25m, account.Balance); } [Fact(Skip = "Remove this Skip property to run this test")] public void Withdraw_twice() { var account = new BankAccount(); account.Open(); account.Deposit(100m); account.Withdraw(80m); account.Withdraw(20m); Assert.Equal(0m, account.Balance); } [Fact(Skip = "Remove this Skip property to run this test")] public void Can_do_multiple_operations_sequentially() { var account = new BankAccount(); account.Open(); account.Deposit(100m); account.Deposit(110m); account.Withdraw(200m); account.Deposit(60m); account.Withdraw(50m); Assert.Equal(20m, account.Balance); } [Fact(Skip = "Remove this Skip property to run this test")] public void Cannot_check_balance_of_closed_account() { var account = new BankAccount(); account.Open(); account.Close(); Assert.Throws(() => account.Balance); } [Fact(Skip = "Remove this Skip property to run this test")] public void Cannot_deposit_into_closed_account() { var account = new BankAccount(); account.Open(); account.Close(); Assert.Throws(() => account.Deposit(50m)); } [Fact(Skip = "Remove this Skip property to run this test")] public void Cannot_deposit_into_unopened_account() { var account = new BankAccount(); Assert.Throws(() => account.Deposit(50m)); } [Fact(Skip = "Remove this Skip property to run this test")] public void Cannot_withdraw_from_closed_account() { var account = new BankAccount(); account.Open(); account.Close(); Assert.Throws(() => account.Withdraw(50m)); } [Fact(Skip = "Remove this Skip property to run this test")] public void Cannot_close_an_account_that_was_not_opened() { var account = new BankAccount(); Assert.Throws(() => account.Close()); } [Fact(Skip = "Remove this Skip property to run this test")] public void Cannot_open_an_already_opened_account() { var account = new BankAccount(); account.Open(); Assert.Throws(() => account.Open()); } [Fact(Skip = "Remove this Skip property to run this test")] public void Reopened_account_does_not_retain_balance() { var account = new BankAccount(); account.Open(); account.Deposit(50m); account.Close(); account.Open(); Assert.Equal(0m, account.Balance); } [Fact(Skip = "Remove this Skip property to run this test")] public void Cannot_withdraw_more_than_deposited() { var account = new BankAccount(); account.Open(); account.Deposit(25m); Assert.Throws(() => account.Withdraw(50m)); } [Fact(Skip = "Remove this Skip property to run this test")] public void Cannot_withdraw_negative() { var account = new BankAccount(); account.Open(); account.Deposit(100m); Assert.Throws(() => account.Withdraw(-50m)); } [Fact(Skip = "Remove this Skip property to run this test")] public void Cannot_deposit_negative() { var account = new BankAccount(); account.Open(); Assert.Throws(() => account.Deposit(-50m)); } [Fact(Skip = "Remove this Skip property to run this test")] public async Task Can_handle_concurrent_transactions() { var account = new BankAccount(); account.Open(); var tasks = new List(); for (int i = 0; i < 500; i++) { tasks.Add(Task.Factory.StartNew(() => { for (int j = 0; j < 100; j++) { account.Deposit(1m); account.Withdraw(1m); } }, TestContext.Current.CancellationToken)); } await Task.WhenAll(tasks.ToArray()); Assert.Equal(0m, account.Balance); } }