feat: implements bank account system with checking and savings accounts, including unit tests

Author: enyabuti

lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/BankAccount.java

@@ -0,0 +1,43 @@
+package com.codedifferently.lesson17.bank;
+
+import com.codedifferently.lesson17.bank.exceptions.InsufficientFundsException;
+import java.util.Set;
+
+/** Base class for all bank accounts. */
+public abstract class BankAccount {
+  private String accountNumber;
+  private double balance;
+  private Set<Customer> owners;
+
+  public BankAccount(String accountNumber, Set<Customer> owners, double initialBalance) {
+    this.accountNumber = accountNumber;
+    this.owners = owners;
+    this.balance = initialBalance;
+  }
+
+  public String getAccountNumber() {
+    return accountNumber;
+  }
+
+  public double getBalance() {
+    return balance;
+  }
+
+  public Set<Customer> getOwners() {
+    return owners;
+  }
+
+  public void withdraw(double amount) throws InsufficientFundsException {
+    if (amount > balance) {
+      throw new InsufficientFundsException("Insufficient funds");
+    }
+    balance -= amount;
+  }
+
+  public void deposit(double amount) {
+    if (amount <= 0) {
+      throw new IllegalArgumentException("Deposit amount must be positive");
+    }
+    balance += amount;
+  }
+}

lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/BankAtm.java

@@ -11,6 +11,7 @@ public class BankAtm {
 
   private final Map<UUID, Customer> customerById = new HashMap<>();
   private final Map<String, CheckingAccount> accountByNumber = new HashMap<>();
+  private final Map<String, SavingsAccount> savingsAccountByNumber = new HashMap<>();
 
   /**
    * Adds a checking account to the bank.
@@ -27,6 +28,21 @@ public void addAccount(CheckingAccount account) {
             });
   }
 
+  /**
+   * Adds a savings account to the bank.
+   *
+   * @param account The account to add.
+   */
+  public void addAccount(SavingsAccount account) {
+    savingsAccountByNumber.put(account.getAccountNumber(), account);
+    account
+        .getOwners()
+        .forEach(
+            owner -> {
+              customerById.put(owner.getId(), owner);
+            });
+  }
+
   /**
    * Finds all accounts owned by a customer.
    *

lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/BusinessCheckingAccount.java

@@ -0,0 +1,16 @@
+package com.codedifferently.lesson17.bank;
+
+import java.util.Set;
+
+/** Represents a business checking account. */
+public class BusinessCheckingAccount extends CheckingAccount {
+  public BusinessCheckingAccount(
+      String accountNumber, Set<Customer> owners, double initialBalance) {
+    super(accountNumber, owners, initialBalance);
+  }
+  /**
+   * Gets the account number.
+   *
+   * @return The account number.
+   */
+}

lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/CheckingAccount.java

@@ -1,10 +1,11 @@
 package com.codedifferently.lesson17.bank;
 
-import com.codedifferently.lesson17.bank.exceptions.InsufficientFundsException;
 import java.util.Set;
 
+import com.codedifferently.lesson17.bank.exceptions.InsufficientFundsException;
+
 /** Represents a checking account. */
-public class CheckingAccount {
+public class CheckingAccount extends BankAccount {
 
   private final Set<Customer> owners;
   private final String accountNumber;
@@ -19,6 +20,7 @@ public class CheckingAccount {
    * @param initialBalance The initial balance of the account.
    */
   public CheckingAccount(String accountNumber, Set<Customer> owners, double initialBalance) {
+    super(accountNumber, owners, initialBalance); 
     this.accountNumber = accountNumber;
     this.owners = owners;
     this.balance = initialBalance;

lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/SavingsAccount.java

@@ -0,0 +1,20 @@
+package com.codedifferently.lesson17.bank;
+
+import java.util.Set;
+
+/** Represents a savings account. */
+public class SavingsAccount extends CheckingAccount {
+
+  public SavingsAccount(String accountNumber, Set<Customer> owners, double initialBalance) {
+    super(accountNumber, owners, initialBalance);
+  }
+
+  /**
+   * Gets the account number.
+   *
+   * @return The account number.
+   */
+  public void depositFunds(Check check) {
+    throw new UnsupportedOperationException("Cannot deposit a check into a savings account");
+  }
+}

lesson_17/bank/bank_app/src/test/java/com/codedifferently/lesson17/bank/SavingsAccountTest.java

@@ -0,0 +1,40 @@
+package com.codedifferently.lesson17.bank;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.Set;
+import org.junit.jupiter.api.Test;
+
+public class SavingsAccountTest {
+  @Test
+  public void testDepositFunds() {
+    // Create a customer
+    Customer customer = new Customer(null, "John Doe");
+
+    // Create a savings account
+    SavingsAccount savingsAccount = new SavingsAccount("123456789", Set.of(customer), 1000.0);
+
+    // Deposit funds into the account
+    savingsAccount.deposit(500.0);
+
+    // Assert that the balance is correct
+    assertEquals(1500.0, savingsAccount.getBalance());
+  }
+
+  @Test
+  public void testDepositCheck() {
+    // Create a customer
+    Customer customer = new Customer(null, "John Doe");
+
+    // Create a savings account
+    SavingsAccount savingsAccount = new SavingsAccount("123456789", Set.of(customer), 1000.0);
+
+    // Attempt to deposit a check into the account
+    assertThrows(
+        UnsupportedOperationException.class,
+        () -> {
+          savingsAccount.depositFunds(new Check(null, 100.0, savingsAccount));
+        });
+  }
+}