Students need test-driven guidance to implement the bank account system described in the README.

Changes

Test Suite (53 tests across 6 classes)

• PersonTest / BusinessTest - Account holder types with basic properties
• AccountTest - Abstract base with balance, transactions, credit/debit operations
• CheckingAccountTest - Overdraft protection behavior (configurable allow/prevent)
• SavingsAccountTest - Interest application + mandatory overdraft protection
• InvestmentAccountTest - Interest on positive/negative balances, no overdraft protection

Stub Implementations

• All classes created with TODO comments and method signatures
• Compiles successfully, tests fail appropriately to guide implementation
• Students see exactly what methods/behavior to implement

Documentation

• TESTING_GUIDE.md - Test structure, implementation order, TDD workflow

Example Test Pattern

@Test
public void testDebitWithOverdraftProtectionEnabled() {
    // Given
    CheckingAccount account = new CheckingAccount(person, 500.0, "CHK005", true);
    
    // When - Attempting to overdraw
    account.debit(600.0);
    
    // Then - Balance unchanged (overdraft protection)
    Assert.assertEquals(500.0, account.getBalance(), 0.01);
}

Tests use Given-When-Then pattern. Run mvn test to see 53 failing tests that become implementation roadmap.

• Fixes Add some unit tests #4

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