SimpleBank

A simple banking ecosystem to demonstrate unit testing and test driven development. SimpleBank consists of types Bank, Account, Money and Person.

Step 1: Write Unit Tests

• Branch: master
• There are just empty unit tests. Every test indicates a requirement.
• Tasks: Write unit tests to fullfil the given requirements.

Step 2: Implement Features

• Branch: withtests
• The branch contains the code for all unit tests. Most BankTests are failing with NotImplementedExceptions.
• Tasks: Implement all Bank methods in order to fix all unit tests.

Step 3: Bug fixing using TDD

• Branch: transferbug
• SimpleBank now contains succeeding tests, all green!
• Tasks: Bank customers have reported a bug. Whenever money is transferred from a valid source account to a non-existent target account the Bank throws an exception. However, the money is removed from the source account! 1) Write a unit test to reproduce the bug, 2) find and fix the bug.

Additional Exercises

• The bank gets a new regulatory requirement: Each transaction (Transfer, Withdraw and Deposit) has to charge a transaction fee on top of the transfer value. Following fees apply from January 1 of next year:
  • Customer origin fee: Switzerland 1%, Germany 0.8%
  • Accounts value fee: 0% if <= 1'000'000, 1% if > 1'000'000
• Extend Money with currency. Transfers from one currency to another have to be recalculated based on the current interbank exchange rate. Consume a forex service to retrieve exchange rates.
• Implement operators for Money so that we can compare (==, !=, >, <) between Money objects.