feat: adds savings account test

Author: AmiyahJo

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

@@ -0,0 +1,47 @@
+package com.codedifferently.lesson17.bank;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import org.junit.jupiter.api.Test;
+
+import com.codedifferently.lesson17.bank.exceptions.CheckNotAllowedException;
+
+public class SavingsAccountTest {
+    @Test
+    void testDeposit() {
+       // Arrange
+        SavingsAccount account = new SavingsAccount("12345678", null, 5.00);
+        account.deposit(200);
+
+        // Assert
+        assertEquals(205.00, account.getBalance()); 
+    }
+
+    @Test
+    void testWithdraw() {
+        // Arrange
+        SavingsAccount account = new SavingsAccount("12345678", null, 0.00);
+        account.deposit(1000);
+
+        // Act
+        account.withdraw(500);
+
+        // Assert
+        assertEquals(500, account.getBalance());
+    }
+
+    @Test
+    void testWriteCheck() {
+        // Arrange
+        SavingsAccount account = new SavingsAccount("12345678", null, 1000.00);
+
+        // Act & Assert
+        CheckNotAllowedException thrown = assertThrows(CheckNotAllowedException.class, () -> {
+            account.writeCheck(100);  
+        });
+
+        // Assert
+        assertEquals("Savings account cannot write checks", thrown.getMessage());
+
+    }
+}