6.6Testing Procedure Error Handling

def test_transfer_funds_insufficient_balance(db):
    """Transfer should fail if source account has insufficient funds."""
    cursor = db.cursor()

    # Set up accounts
    cursor.execute("""
        INSERT INTO accounts (id, balance) VALUES
        ('acct-a', 100.00),
        ('acct-b', 50.00)
    """)

    # Attempt transfer exceeding balance
    with pytest.raises(Exception):  # Specific exception depends on implementation
        cursor.execute("SELECT transfer_funds('acct-a', 'acct-b', 200.00)")

    # Verify no money was moved (transaction should be rolled back internally)
    cursor.execute("SELECT balance FROM accounts WHERE id = 'acct-a'")
    assert cursor.fetchone()[0] == 100.00  # Unchanged
    cursor.execute("SELECT balance FROM accounts WHERE id = 'acct-b'")
    assert cursor.fetchone()[0] == 50.00   # Unchanged